ALUMINUM ALLOY PRODUCTS AND METHODS OF MAKING THE SAME

FIELD OF THE INVENTION

[0001] Broadly, the present disclosure relates to aluminum alloy products and methods of making the same.

BACKGROUND

[0002] The Aluminum Association Global Advisory Group defines“aluminum alloys” as “aluminum which contains alloying elements, where aluminum predominates by mass over each of the other elements and where the aluminum content is not greater than 99.00%.” (Global Advisory Group GAG - Guidance, GAG Guidance Document 001, Terms and Definitions, Edition 2009-01, March 2009, § 2.2.2.) An“alloying element” is a“metallic or non-metallic element which is controlled within specific upper and lower limits for the purpose of giving the aluminum alloy certain special properties” (§ 2.2.3). A casting alloy is defined as an“alloy primarily intended for the production of castings,” (§ 2.2.5) and a“wrought alloy” is an“alloy primarily intended for the production of wrought products by hot and/or cold working” (§ 2.2.5).

SUMMARY OF THE DISCLOSURE

[0003] Broadly, the present patent application relates to additively manufactured products and methods for making the same. In some embodiments, a method includes additively manufacturing an aluminum alloy product. After the additive manufacturing, the aluminum alloy products may have fine (e.g., having an average grain size of not greater than 10 micrometers), equiaxed grains. In some embodiments, the method includes heat treatment processes (e.g., at least one of solution heat treatment and annealing). The heat treatment processes may enlarge (e.g., coarsen) the grains of the additively manufactured products (e.g., increase the average grain size). In some embodiments, the method combines (i) additive manufacturing processing to form additively manufactured products having fine, equiaxed grains with (ii) heat treating to increase the average grain size. Due to at least the heat treatment processes, a heat treated aluminum alloy product may realize at least one improved property. For instance, a heat treated additively manufactured aluminum alloy product may realize an improvement in at least one of strength, fatigue, fatigue crack growth, creep, fracture toughness and corrosion resistance. In some embodiments, a heat treated additively manufactured aluminum alloy product comprises large equiaxed grains (defined below). a. Additively Manufactured Aluminum Alloy Products

[0004] As noted above, the additively manufactured aluminum alloy products may realize a unique combination of microstructural features. Various non-limiting examples of these microstructural features are provided below.

i. Microstructure

[0005] In one embodiment, an additively manufactured aluminum alloy product comprises a plurality of grains, where the plurality of grains comprise large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of greater than 10 micrometers and an average aspect ratio of less than 4: 1, and where at least 20% of the plurality of grains are large equiaxed grains.

[0006] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where at least 30% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where at least 40% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where at least 50% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where at least 60% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where at least 70% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where at least 80% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where at least 90% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where at least 95% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 100% of the plurality of grains are large equiaxed grains.

[0007] As used herein, the“grain size” is calculated by the following equation:

4Ai

vz = square root (—) • A i is the area of the individual grain as measured using commercial software Edax OIM version 8.0 or equivalent; and

• vi is the calculated grain size assuming the grain is a circle.

[0008] As used herein, the“area weighted average grain size” is calculated by the following equation:

v-bar

• A i is the area of each individual grain as measured using commercial software Edax OIM version 8.0 or equivalent;

• vi is the calculated grain size assuming the grain is a circle; and

• v-bar is the area weighted average grain size.

[0009] As used herein,“equiaxed grains” means grains having an average aspect ratio of less than 4: 1 as measured in the XY, YZ, and XZ planes. The“aspect ratio” is determined using commercial software Edax OIM version 8.0 or equivalent. The commercial software fits an ellipse to the perimeter points of the grain. As used herein,“aspect ratio” is the inverse of: the length of the minor axis of the ellipse divided by the length of the major axis of the ellipse as determined using commercial software.

[0010] As used herein,“grain size” and“aspect ratio” are determined based on a two- dimensional plane that includes the build direction of the product.

[0011] As used herein,“large equiaxed grains” are equiaxed grains having a grain size greater than 10 micrometers.

[0012] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where not greater than 30% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where not greater than 40% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where not greater than 50% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where not greater than 60% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where not greater than 70% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where not greater than 80% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where not greater than 90% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where not greater than 95% of the plurality of grains are large equiaxed grains.

[0013] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 20-100% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 30-100% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 40- 100% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 50-100% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 60-100% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 70-100% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 80-100% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 90-100% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 95-100% of the plurality of grains are large equiaxed grains.

[0014] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 20-95% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 20-90% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 20- 80% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 20-70% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 20-60% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 20-50% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 20-40% of the plurality of grains are large equiaxed grains. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where 20-30% of the plurality of grains are large equiaxed grains.

[0015] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having large equiaxed grains, where the large equiaxed grains have an average aspect ratio of not greater than 4: 1. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having large equiaxed grains, where the large equiaxed grains have an average aspect ratio of not greater than 3 : 1. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having large equiaxed grains, where the large equiaxed grains have an average aspect ratio of not greater than 2: 1. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having large equiaxed grains, where the large equiaxed grains have an average aspect ratio of not greater than 1.5: 1. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having large equiaxed grains, where the large equiaxed grains have an average aspect ratio of not greater than 1.1 : 1.

[0016] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having large equiaxed grains, where the large equiaxed grains have an average aspect ratio of 1.1 : 1 to 4: 1. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having large equiaxed grains, where the large equiaxed grains have an average aspect ratio of 1.5: 1 to 4: 1. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having large equiaxed grains, where the large equiaxed grains have an average aspect ratio of 2: 1 to 4: 1. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having large equiaxed grains, where the large equiaxed grains have an average aspect ratio of 3: 1 to 4: 1. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having large equiaxed grains, where the large equiaxed grains have an average aspect ratio of 1.1 : 1 to 2: 1. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having large equiaxed grains, where the large equiaxed grains have an average aspect ratio of 1.5: 1 to 3: 1. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having large equiaxed grains, where the large equiaxed grains have an average aspect ratio of 2: 1 to 3: 1.

[0017] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of at least 10 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of at least 20 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of at least 50 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of at least 80 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of at least 100 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of at least 200 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of at least 300 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of at least 400 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of at least 500 micrometers.

[0018] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of not greater than 20 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of not greater than 50 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of not greater than 80 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of not greater than 100 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of not greater than 200 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of not greater than 300 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of not greater than 400 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of not greater than 500 micrometers.

[0019] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 10 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 20 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 50 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 80 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 100 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 200 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 300 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 400 to 500 micrometers. [0020] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 10 to 400 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 10 to 300 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 10 to 200 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 10 to 100 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 10 to 80 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 10 to 50 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 10 to 20 micrometers.

[0021] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 20 to 400 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 50 to 200 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 80 to 300 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an area weighted average grain size of 100 to 200 micrometers.

[0022] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of at least 10 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of at least 20 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of at least 50 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of at least 80 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of at least 100 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of at least 200 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of at least 300 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of at least 400 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of at least 500 micrometers.

[0023] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of not greater than 20 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of not greater than 50 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of not greater than 80 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of not greater than 100 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of not greater than 200 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of not greater than 300 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of not greater than 400 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of not greater than 500 micrometers.

[0024] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 10 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 20 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 50 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 80 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 100 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 200 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 300 to 500 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 400 to 500 micrometers. [0025] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 10 to 300 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 10 to 200 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 10 to 100 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 10 to 80 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 10 to 50 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 10 to 20 micrometers.

[0026] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 20 to 400 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 50 to 200 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 80 to 300 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains of having large equiaxed grains, where the large equiaxed grains have an area weighted average grain size of 100 to 200 micrometers.

[0027] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains, where the plurality of grains comprise large equiaxed grains and remainder grains, where not greater than 99% of the plurality of grains are large equiaxed grains and at least 1% of the plurality of grains are remainder grains, where the remainder grains realize at least one of a grain size of not greater than 10 micrometers and an average aspect ratio of at least 4: 1.

[0028] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having remainder grains, where an area weighted average grain size of the remainder grains is less than 8 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having remainder grains, where an area weighted average grain size of the remainder grains is less than 5 micrometers. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having remainder grains, where an area weighted average grain size of the remainder grains is less than 3 micrometers.

[0029] In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having remainder grains, where an average aspect ratio of at least 5: 1. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having remainder grains, where an average aspect ratio of at least 6: 1. In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises a plurality of grains having remainder grains, where an average aspect ratio of at least 7: 1.

ii. Composition

[0030] The new additively manufactured aluminum alloy products may be made from any suitable aluminum alloy composition. In one embodiment, an additively manufactured aluminum alloy product comprises (or may consist essentially of, or consist of) any of the lxxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx, and 8xxx aluminum alloys, as defined by the Aluminum Association document ANSI H35.1 entitled,“American National Standard Alloy and Temper Designation Systems for Aluminum” (2009), pages 4-5. In another embodiment, an additively manufactured aluminum alloy product comprises (or may consist essentially of, or consist of) any of the lxx, 2xx, 3xx, 4xx, 5xx, 7xx, 8xx and 9xx aluminum casting and ingot alloys, as defined by the Aluminum Association document ANSI H35.1 entitled,“American National Standard Alloy and Temper Designation Systems for Aluminum” (2009), pages 6-7. Some suitable aluminum alloy compositions for use with the present disclosure include the lxxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx and 8xxx aluminum alloy compositions of the Aluminum Association document“International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys” (2015) (a.k.a., the“Teal Sheets”), and the lxx, 2xx, 3xx, 4xx, 5xx, 7xx, 8xx and 9xx aluminum alloy compositions of the Aluminum Association document “Designations and Chemical Composition Limits for Aluminum Alloys in the Form of Castings and Ingot” (2009) (a.k.a.,“the Pink Sheets”). In one or more of the described embodiments, an additively manufactured aluminum alloy product comprises an aluminum alloy selected from the group consisting of lxxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx, and 8xxx aluminum alloys.

[0031] In one embodiment, an additively manufactured product comprises an aluminum alloy composition falling within the scope of a lxxx aluminum alloy. As used herein, a“lxxx aluminum alloy” is an aluminum alloy comprising at least 99.00 wt. % Al, as defined by ANSI H35.1 (2009), optionally comprising tolerable levels of oxygen (e.g., from about 0.01 to 0.20 wt. % O) therein due to normal additive manufacturing processes. The term“lxxx aluminum alloy” as used herein includes lxx alloys as defined by ANSI H35.1 (2009). A lxxx aluminum alloy includes pure aluminum products (e.g., 99.99% Al products). As used herein, the term “lxxx aluminum alloy” only refers to the composition and not any associated processing, i.e., as used herein a lxxx aluminum alloy product does not need to be a wrought product to be considered a lxxx aluminum alloy composition / product described herein.

[0032] In one embodiment, an additively manufactured product comprises an aluminum alloy composition falling within the scope of a 2xxx aluminum alloy, as defined by ANSI H35.1 (2009), optionally comprising tolerable levels of oxygen (e.g., from about 0.01 to 0.20 wt. % O) therein due to normal additive manufacturing processes. A 2xxx aluminum alloy is an aluminum alloy comprising copper (Cu) as the predominate alloying ingredient, except for aluminum. The term“2xxx aluminum alloy” as used herein includes 2xx alloys as defined by ANSI H35.1 (2009). Also, as used herein, the term“2xxx aluminum alloy” only refers to the composition and not any associated processing, i.e., as used herein a 2xxx aluminum alloy product does not need to be a wrought product to be considered a 2xxx aluminum alloy composition / product described herein.

[0033] In one embodiment, an additively manufactured product comprises an aluminum alloy composition falling within the scope of a 3xxx aluminum alloy, as defined by ANSI H35.1 (2009), optionally comprising tolerable levels of oxygen (e.g., from about 0.01 to 0.20 wt. % O) therein due to normal additive manufacturing processes. A 3xxx aluminum alloy is an aluminum alloy comprising manganese (Mn) as the predominate alloying ingredient, except for aluminum. Also, as used herein, the term“3xxx aluminum alloy” only refers to the composition and not any associated processing, i.e., as used herein a 3xxx aluminum alloy product does not need to be a wrought product to be considered a 3xxx aluminum alloy composition / product described herein.

[0034] In one embodiment, an additively manufactured product comprises an aluminum alloy composition falling within the scope of a 4xxx aluminum alloy, as defined by ANSI H35.1 (2009), optionally comprising tolerable levels of oxygen (e.g., from about 0.01 to 0.20 wt. % O) therein due to normal additive manufacturing processes. A 4xxx aluminum alloy is an aluminum alloy comprising silicon (Si) as the predominate alloying ingredient, except for aluminum. The term“4xxx aluminum alloy” as used herein includes both 3xx alloys and 4xx alloys as defined by ANSI H35.1 (2009). Also, as used herein, the term“4xxx aluminum alloy” only refers to the composition and not any associated processing, i.e., as used herein a 4xxx aluminum alloy product does not need to be a wrought product to be considered a 4xxx aluminum alloy composition / product described herein.

[0035] In one embodiment, an additively manufactured product comprises an aluminum alloy composition falling within the scope of a 5xxx aluminum alloy, as defined by ANSI H35.1 (2009), optionally comprising tolerable levels of oxygen (e.g., from about 0.01 to 0.20 wt. % O) therein due to normal additive manufacturing processes. A 5xxx aluminum alloy is an aluminum alloy comprising magnesium (Mg) as the predominate alloying ingredient, except for aluminum. The term“5xxx aluminum alloy” as used herein includes 5xx alloys as defined by ANSI H35.1 (2009). Also, as used herein, the term“5xxx aluminum alloy” only refers to the composition and not any associated processing, i.e., as used herein a 5xxx aluminum alloy product does not need to be a wrought product to be considered a 5xxx aluminum alloy composition / product described herein.

[0036] In one embodiment, an additively manufactured product comprises an aluminum alloy composition falling within the scope of a 6xxx aluminum alloy, as defined by ANSI H35.1 (2009), optionally comprising tolerable levels of oxygen (e.g., from about 0.01 to 0.20 wt. % O) therein due to normal additive manufacturing processes. A 6xxx aluminum alloy is an aluminum alloy comprising both silicon and magnesium, and in amounts sufficient to form the precipitate Mg ₂ Si. Also, as used herein, the term“6xxx aluminum alloy” only refers to the composition and not any associated processing, i.e., as used herein a 6xxx aluminum alloy product does not need to be a wrought product to be considered a 6xxx aluminum alloy composition / product described herein. [0037] In one embodiment, an additively manufactured product comprises an aluminum alloy composition falling within the scope of a 7xxx aluminum alloy, as defined by ANSI H35.1 (2009), optionally comprising tolerable levels of oxygen (e.g., from about 0.01 to 0.20 wt. % O) therein due to normal additive manufacturing processes. A 7xxx aluminum alloy is an aluminum alloy comprising zinc (Zn) as the predominate alloying ingredient, except for aluminum. The term“7xxx aluminum alloy” as used herein includes 7xx alloys as defined by ANSI H35.1 (2009). Also, as used herein, the term“7xxx aluminum alloy” only refers to the composition and not any associated processing, i.e., as used herein a 7xxx aluminum alloy product does not need to be a wrought product to be considered a 7xxx aluminum alloy composition / product described herein.

[0038] In one embodiment, an additively manufactured product comprises an aluminum alloy composition falling within the scope of a 8xxx aluminum alloy, as defined by ANSI H35.1 (2009), optionally comprising tolerable levels of oxygen (e.g., from about 0.01 to 0.20 wt. % O) therein due to normal additive manufacturing processes. A 8xxx aluminum alloy is any aluminum alloy that is not a lxxx-7xxx aluminum alloy. Examples of 8xxx aluminum alloys include alloys having iron or lithium as the predominate alloying element, other than aluminum. The term“8xxx aluminum alloy” as used herein includes 8xx alloys and 9xx alloys as defined by ANSI H35.1 (2009). As noted in ANSI H35.1 (2009), the 9xx alloy compositions are aluminum alloys with“other elements” other than copper, silicon, magnesium, zinc, and tin, as the major alloying element. Also, as used herein, the term“8xxx aluminum alloy” only refers to the composition and not any associated processing, i.e., as used herein an 8xxx aluminum alloy product does not need to be a wrought product to be considered an 8xxx aluminum alloy composition / product described herein.

[0039] In some embodiments, an additively manufactured aluminum alloy product may include one or more grain refiners (defined below). The inclusion of grain refmer(s) within the alloy may have several benefits, including facilitating the production of equiaxed grains and/or improved mechanical properties. In this regard, the grain refmer(s) may facilitate the production of equiaxed grains that may increase the ductility of the aluminum alloy products. Increased ductility may facilitate the production of crack-free aluminum alloy products. Furthermore, the inclusion of an appropriate amount of grain refmer(s) (e.g., not greater than 6 wt. %) may improve mechanical properties (e.g., strength, ductility, among others). However, without being bound by any mechanism or theory, too much grain refmer(s) (e.g., greater than 6 wt. %) may decrease the strength, fatigue resistance, and/or fracture toughness of the aluminum alloy product, and/or may inhibit the ability to control and/or tailor grain growth during heat treatment. Thus, in one embodiment, an additively manufactured aluminum alloy product comprises a sufficient amount of the grain refmer(s) to facilitate production of a crack-free aluminum alloy product (e.g., via equiaxed grains and/or via fine grains having an area weighted average grain size of not greater than 10 micrometers)), but the amount of grain refmer(s) in the additively manufactured aluminum alloy product may be tailored so that the product retains its strength (e.g., tensile yield strength (TYS) and/or ultimate tensile strength (UTS)), fatigue resistance, and/or fracture toughness. In some embodiments, the amount of grain refmer(s) may be limited such that the strength of the aluminum alloy product substantially corresponds to its strength without the grain refmer(s) (e.g., within 5 ksi; within 1-4 ksi). In some embodiments, the amount of grain refmer(s) may be limited such that the strength of the aluminum alloy product substantially corresponds to its strength without the grain refmer(s) (e.g., within 5%).

[0040] As used herein, “grain refiner” means a nucleant or nucleants that facilitates aluminum crystal formation. Suitable grain refmer(s) include ceramic materials, intermetallic materials, and combinations thereof, among others.

[0041] In one embodiment, an additively manufactured aluminum alloy product comprises at least 0.1 wt. % of the grain refmer(s), or at least 0.5 wt. % of the grain refmer(s), or at least 0.5 wt. % of the grain refmer(s), or at least 1 wt. % of the grain refmer(s), or at least 2 wt. % of the grain refmer(s), or at least 3 wt. % of the grain refmer(s), or at least 4 wt. % of the grain refmer(s), or at least 5 wt. % of the grain refmer(s), or more.

[0042] In one embodiment, an additively manufactured aluminum alloy product comprises not greater than 6 wt. % of the grain refmer(s), or not greater than 5 wt. % of the grain refmer(s), or not greater than 4 wt. % of the grain refmer(s), or not greater than 3 wt. % of the grain refmer(s), or not greater than 2 wt. % of the grain refmer(s), or not greater than 1 wt. % of the grain refmer(s), or less.

[0043] In one embodiment, an additively manufactured aluminum alloy product comprises 0.1 - 6 wt. % of the grain refmer(s). In another embodiment, an additively manufactured aluminum alloy product comprises 0.1 - 5 wt. % of the grain refmer(s). In yet another embodiment, an additively manufactured aluminum alloy product comprises 0.1 - 4 wt. % of the grain refmer(s). In another embodiment, an additively manufactured aluminum alloy product comprises 0.1 - 3 wt. % of the grain refmer(s). In yet another embodiment, an additively manufactured aluminum alloy product comprises 0.1 - 2 wt. % of the grain refmer(s). In another embodiment, an additively manufactured aluminum alloy product comprises 0.1 - 1 wt. % of the grain refmer(s). In yet another embodiment, an additively manufactured aluminum alloy product comprises 1 - 6 wt. % of the grain refmer(s). In another embodiment, an additively manufactured aluminum alloy product comprises 2 - 6 wt. % of the grain refmer(s). In yet another embodiment, an additively manufactured aluminum alloy product comprises 3 - 6 wt. % of the grain refmer(s). In another embodiment, an additively manufactured aluminum alloy product comprises 4 - 6 wt. % of the grain refmer(s). In yet another embodiment, an additively manufactured aluminum alloy product comprises 5 - 6 wt. % of the grain refmer(s). In another embodiment, an additively manufactured aluminum alloy product comprises 0.5 - 5 wt. % of the grain refmer(s). In yet another embodiment, an additively manufactured aluminum alloy product comprises 0.5 - 4 wt. % of the grain refmer(s). In another embodiment, an additively manufactured aluminum alloy product comprises 0.5 - 3 wt. % of the grain refmer(s). In yet another embodiment, an additively manufactured aluminum alloy product comprises 0.5 - 2 wt. % of the grain refmer(s).

[0044] In one approach, a ceramic material is used to facilitate grain refinement. Examples of ceramics include oxide materials, boride materials, carbide materials, nitride materials, silicon materials, carbon materials, and/or combinations thereof. Some additional examples of ceramics include metal oxides, metal borides, metal carbides, metal nitrides and/or combinations thereof. Additionally, some non-limiting examples of ceramics include: TiB, TiB ₂ , TiC, SiC, AI2O3, B ₄ C, BN, S13N4, AI4C3, A1N, their suitable equivalents, and/or combinations thereof. In another approach, intermetallic particles are used to facilitate grain refinement. For instance, the aluminum alloy compositions described herein may include materials that may facilitate the formation of intermetallic particles (e.g., during solidification). In this regard, non-limiting examples of such materials that may be used include titanium (Ti), zirconium (Zr), scandium (Sc), vanadium (V) and hafnium (Hf), optionally in elemental form, among others. Additional non-limiting embodiments of such materials that may be used include niobium (Nb), tantalum (Ta), tungsten (W), and molybdenum (Mo). In some embodiments, both ceramic materials and intermetallic particles are utilized in an aluminum alloy to refine the grain structure and/or tailor the microstructure of the resulting additively manufactured aluminum alloy product.

[0045] In one embodiment, an additively manufactured aluminum alloy product comprises at least one of TiB ₂ , TiC, AI ₃ T1, and combinations thereof. In this regard, AI ₃ T1 may form during solidification (e.g., in the presence of Ti; at the surface of TiB ₂ particles). b. Additive Manufacturing

[0046] As noted above, the new aluminum alloy products described herein may be produced via additive manufacturing followed by heat treatment. As used herein,“additive manufacturing” means“a process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies”, as defined in ASTM F2792-l2a entitled “Standard Terminology for Additively Manufacturing Technologies”.

[0047] In one embodiment, and now with reference to FIG. 1, an embodiment for producing an additively manufactured aluminum alloy product is shown (10). The method (10) may comprise additively manufacturing an additively manufactured aluminum alloy product (100), optionally deforming at least a portion of the additively manufactured aluminum alloy product (110), heating the additively manufactured product (120), cooling the additively manufactured product (130), and any optional post processing (140). These steps are described in further detail below. However, prior to describing these steps, suitable feedstocks for the additive manufacturing processes described herein are discussed. i. Feedstocks

[0048] As noted above, various methods of producing the additively manufactured aluminum alloy products may be employed. In this regard, the additively manufactured aluminum alloy products may be produced via additive manufacturing using a variety of additive manufacturing feedstocks. In this aspect, the additive manufacturing feedstock may be capable of realizing one or more of (i) equiaxed grains and (ii) an area weighted average grain size of not greater than 10 micrometers.

A. Feedstock Compositions

[0049] Any suitable aluminum alloy compositions may be used as additive manufacturing feedstocks, such as any of the aluminum alloy compositions described in Section a.ii, above. In one or more of the described embodiments, an additive manufacturing feedstock comprises an aluminum alloy, where the aluminum alloy is selected from the group consisting of lxxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx, and 8xxx aluminum alloys.

[0050] Furthermore, any suitable grain refmer(s) may be included in an additive manufacturing feedstock, such as any of the grain refiners described in Section a.ii, above. In one or more of the described embodiments, an additive manufacturing feedstock comprises aluminum and at least one grain refiner. In one or more of the described embodiments, an additive manufacturing feedstock comprises a sufficient amount of the grain refmer(s) to realize a first plurality of grains having a first area weighted average grain size of not greater than 10 micrometers.

[0051] In one or more of the described embodiments, an additive manufacturing feedstock comprises 0.1 weight percent to 6 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises 0.1 weight percent to 5 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises 0.1 weight percent to 4 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises 0.1 weight percent to 3 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises 0.1 weight percent to 2 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises 0.1 weight percent to 1 weight percent of the grain refmer(s).

[0052] In one or more of the described embodiments, an additive manufacturing feedstock comprises 1 weight percent to 6 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises 2 weight percent to 6 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises 3 weight percent to 6 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises 4 weight percent to 6 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises 5 weight percent to 6 weight percent of the grain refmer(s).

[0053] In one or more of the described embodiments, an additive manufacturing feedstock comprises 0.5 weight percent to 5 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises 0.5 weight percent to 4 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises 0.5 weight percent to 3 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises 0.5 weight percent to 2 weight percent of the grain refmer(s).

[0054] In one or more of the described embodiments, an additive manufacturing feedstock comprises at least 0.5 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises at least 1 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises at least 2 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises at least 3 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises at least 4 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises at least 5 weight percent of the grain refmer(s).

[0055] In one or more of the described embodiments, an additive manufacturing feedstock comprises not greater than 1 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises not greater than 2 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises not greater than 3 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises not greater than 4 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises not greater than 5 weight percent of the grain refmer(s). In one or more of the described embodiments, an additive manufacturing feedstock comprises not greater than 6 weight percent of the grain refmer(s).

[0056] In one or more of the described embodiments, an additive manufacturing feedstock comprises a sufficient amount of at least one grain refiner to facilitate the formation of an additively manufactured aluminum alloy product having equiaxed grains (e.g., having an area weighted average grain size of not greater than 10 microns).

B. Powder Feedstocks

[0057] In some embodiments the additive manufacturing feedstock is comprised of one or more powders. In this regard, the powder(s) used to create the final additively manufactured product may be of any suitable composition, including any combination of metallic, alloy, and non-metallic (e.g., ceramic material) powders. For instance, any combination of metallic powders, alloy powders, and/or non-metallic powders may be used. Shavings are types of particles.

[0058] The additive manufacturing powder feedstock may be comprised of any combination of metallic powders, alloy powders, and non-metallic powders (e.g., ceramic powders). For instance, any combination of metallic powders, alloy powders, and/or non- metallic powders may be used to realize an aluminum alloy composition described above. Furthermore, an additive manufacturing feedstock powder may comprise metallic powders and/or alloy powders, where the particles comprise the metallic powders and/or alloy particles having grain refining material therein (e.g., ceramic materials). By way of non-limiting example, an additive manufacturing feedstock powder may be comprised of alloy particles, and the alloy particles may include a plurality of non-metallic particles therein, wherein the non-metallic particles have a smaller size than the alloy particles. For instance, an additive manufacturing feedstock may be comprised of aluminum alloy particles having a plurality of non-metallic particles (e.g., a ceramic, such as TiB ₂ ) particles may be embedded in the aluminum alloy particles.

[0059] For powder additive manufacturing feedstocks, the powder itself may comprise one or more of (i) equiaxed grains and (ii) an average grain size of not greater than 10 micrometers. The additive manufacturing feedstock powders may be produced via any suitable method. In one embodiment, the powder is produced via a process employing rapid solidification (e.g., at least l000°C per second). In some embodiments, the aluminum alloy powder is produced via a method having a sufficient solidification rate to facilitate production of a powder having one or more of (i) equiaxed grains and (ii) an average grain size of not greater than 10 micrometers. In this regard, the aluminum alloy powder may be produced via any one of plasma atomization, gas atomization, or impingement of a molten aluminum alloy (e.g., solidification of an impinging molten metal droplet on a cold substrate) in order to produce feedstock suitable for additive manufacturing.

C. Other Feedstocks

[0060] Aside from powder, other additive manufacturing feedstocks may be used. Other additive manufacturing feedstocks include wire and sheet. In some embodiments, the additive manufacturing feedstock is comprised of one or more wires. A ribbon is a type of wire. The wires may find utility in wire-based additive manufacturing methods. For instance, wire-based additive manufacturing methods that utilize one or more electron beams and/or plasma arcs may be used. In some embodiments, the additive manufacturing feedstock is comprised of one or more sheets. Foil is a type of sheet. Sheets may be used in additive manufacturing processes such as sheet lamination, per ASTM F2792-l2a.

[0061] In some embodiments, an additive manufacturing feedstock is comprised of one or more powders, one or more wires, one or more sheets, and combinations thereof. ii. Example Additive Manufacturing Processes

[0062] Referring now to FIG. 1, as it relates to the additive manufacturing step (100), the new aluminum alloy products may be additionally manufactured via any appropriate additive manufacturing technique described ASTM F2792-l2a, such as binder jetting, directed energy deposition, material extrusion, material jetting, powder bed fusion, or sheet lamination, among others. In one embodiment, an additive manufacturing process includes depositing successive layers of one or more powders and then selectively melting and/or sintering the powders to create, layer-by-layer, an aluminum alloy product. In one embodiment, an additive manufacturing processes uses one or more of Selective Laser Sintering (SLS), Selective Laser Melting (SLM), and Electron Beam Melting (EBM), among others. In one embodiment, an additive manufacturing process uses an EOSINT M 280 Direct Metal Laser Sintering (DMLS) additive manufacturing system, or comparable system, available from EOS GmbH (Robert- Stirling-Ring 1, 82152 Krailling/Munich, Germany).

[0063] As one specific example, additive manufacturing processes employing metal powder may be used, such as selective laser sintering and/or binder jetting. This metal powder may be dispersed in a bed, and selective laser sintering may be employed and/or a binder may be selectively jetted onto the powder. This process may be repeated, as appropriate, until a green additively manufactured product is completed, after which the green additively manufactured product may be further processed, such as by sintering and/or HIP’ing (hot isostatic pressing), thereby producing a final additively manufactured product. After this final additively manufactured product is completed, it may be subjected to the deforming (110) and/or heating steps (120), as described below.

[0064] As another specific example, directed energy deposition may be used, where one or more metal powders are sprayed in a controlled environment, and concomitant to the spraying, a laser is used to melt and/or solidify the sprayed metal powder(s). This spraying and concomitant energy deposition may be repeated, as necessary to facilitate production of a final additively manufactured aluminum alloy product. After this final additively manufactured product is completed, it may be subjected to the deforming (110) and/or heating (120) steps, as described below.

[0065] With reference now to FIGS. 1 and 3, in some embodiments, the additively manufacturing (100) may comprise selectively heating at least a portion of an additive manufacturing feedstock (101) to a temperature above a liquidus temperature of the additive manufacturing feedstock (e.g., via an energy source such as a laser), thereby forming a molten pool (104), cooling the molten pool (102), thereby forming a solidified mass. The cooling the molten pool may include rapidly solidifying (105) the molten pool. For instance, in one or more of the described embodiments, the cooling the molten pool (102) comprises cooling at a cooling rate of at least 1,000° C per second. In one or more of the described embodiments, the cooling rate is at least 10,000° C per second. In one or more of the described embodiments, the cooling rate is at least 100,000° C per second. In one or more of the described embodiments, the cooling rate is at least 1,000,000° C per second. The selectively heating step (101) and the cooling the molten pool step (102) may be repeated (103) until the additively manufactured aluminum alloy product is completed. Once the additively manufactured product has been completed (106), the additively manufactured aluminum alloy product may be optionally deformed (110), heated (120), cooled (130) and optionally post processed (140).

[0066] As used herein, the term“liquidus” temperature means the temperature above which a product is completely liquid.

[0067] In one embodiment (not illustrated), the additive manufacturing an aluminum alloy product step (100) includes the steps of: (a) dispersing an additive manufacturing feedstock (e.g., a metal powder) in a bed (or other suitable container), (b) selectively heating at least a portion of the additive manufacturing feedstock (e.g., via an energy source or laser) to a temperature above the liquidus temperature of the particular body to be formed, thereby forming a molten pool, and (c) cooling the molten pool thereby forming a solidified mass. The solidified mass may realize, for instance, one or more of (i) equiaxed grains and (ii) an average grain size of not greater than 10 micrometers. Steps (a)-(c) may be repeated as necessary until the product is completed, i.e., until the final additively manufactured product is formed / completed. iii. Deforming

[0068] Referring now to FIG. 2, in some embodiments, an aluminum alloy product is deformed (110). In some embodiments, the deforming (110) comprises working (112). The working (112) may include hot working and/or cold working. The working (112) may include working all or a portion of the product. The working (112) may include, for instance, rolling, extruding, forging, and other known methods of working aluminum alloy products. In one embodiment, the working (112) comprises die forging the final additively manufactured product into the final worked product, wherein the final worked product is a complex shape (e.g., having a plurality of non-planar surfaces). As noted above, one or more of the microstructural features described above (e.g., large equiaxed grains, remainder grains) may be retained after one or more of the working steps (112). In one embodiment, the deforming (110) comprises working (e.g., cold working) at least a portion of a surface of an additively manufactured aluminum alloy product, such as by (i) shot peening or grit blasting (e.g., with metallic, glass or ceramic particles) and/or (ii) shot peening through laser processing (laser shot peening / laser peening). In other embodiments, the deforming step (110) is absent of working (e.g., when HIP’ing is employed, as described below).

[0069] Referring now to FIGS. 1-3, as described in further detail below, a heating step (120) is employed during the method (10) of making an additively manufactured aluminum alloy product. In one embodiment, the deforming (110) and the heating (120) steps are performed sequentially. In another embodiment, a deforming step (110) and a heating step (120) may be performed concomitantly (e.g., when hot isostatic pressing is employed). Any number of deforming (110) and heating (120) steps may be employed, and such steps may be performed once, multiple times, and/or iteratively.

[0070] In one or more of the described embodiments, the deforming step (110) is performed iteratively during the method (10) (not illustrated). For instance, the deforming may occur between the building of successive additively manufactured layers, or every n ^th additively manufactured layer, or portions thereof. In one or more of the described embodiments, the deforming step (110) is performed on at least a portion of the surface of the additively manufactured aluminum alloy product (e.g., the outer surface, or portion thereof, of the final additively manufactured aluminum alloy product).

iv. Post-Additive Manufacturing Heat Treatment

[0071] With continued reference to FIGS. 1-3, in one or more described embodiments, the method (10) comprises heating (120) an additively manufactured aluminum alloy product and then cooling (130) the additively manufactured aluminum alloy product. The heating step (120) may be conducted using any type of heat treatment method including, but not limited to, infrared, radiant-tube, gas-fired or electric furnace, direct resistance and/or induction heat treatment. In one or more of the described embodiments, the heating step (120) comprises at least one of solution heat treating and annealing the additively manufactured aluminum alloy product.

[0072] In one embodiment, the term“anneal” refers to a heating process (120) that primarily causes recovery, recrystallization, and/or grain growth of the metal to occur. In some embodiments, annealing may further include dissolution of soluble particles based, at least in part, on the size of the soluble particles and the annealing temperature. In some embodiments, temperatures used in annealing aluminum alloys range up to the solidus temperature of the aluminum alloy. In some embodiments, temperatures used in annealing aluminum alloys range from about 500 to 900 degrees F. In other embodiments, temperatures used in annealing aluminum alloys range from about 500 to 1100 degrees F. [0073] In one embodiment, the term“solution heat treatment” refers to a heating process (120) in which the metal is held at a high temperature so as to cause at least some soluble particles of the alloying elements to dissolve into solid solution. In some embodiments, the terms“solution heat treatment” and the like (e.g., "solutionizing",“solution heat treating and quenching”), means heating an alloy body to a suitable temperature, generally above a solvus temperature, holding at that temperature long enough to allow soluble elements to enter into solid solution, and cooling rapidly (i.e., quenching) enough to hold the elements in solid solution. The quenching may facilitate production of a supersaturated solid solution. Suitable methods for quenching may include quenching via air or a liquid (e.g., water). Solution heat treatments may be useful, for instance, for alloys that may be precipitation hardened. For instance, certain aluminum alloys (e.g., 2xxx, 6xxx, and 7xxx aluminum alloys) may be precipitation hardened (e.g., to increase strength), as described in greater detail below. Various combinations of (i) solution heat treating and quenching and (ii) aging (142) steps (see FIG. 2 and Section b.vi) may be performed. For instance, an aluminum alloy may be processed to one of a Tl, T2, T3, T4, T5, T6, T7, T8, T9 or T10 temper, as defined in ANSI H35.1 (2009). Temperatures used in solution heat treatment are generally higher than those used in annealing, and range from above the solvus temperature to below the solidus temperature of the heat treated product. In some embodiments, solution heat treatment may be conducted to about 1100° F.

[0074] In one or more of the described embodiments, the heating (120) increases the alloys quench insensitivity (e.g., due to the increase in the area weighted average grain size as per Section b.v, below). In one or more of the described embodiments, the heating (120) increases the area weighted average size of the first plurality of grains of the additively manufactured aluminum alloy product. In some embodiments, increasing the area weighted average grain size of the first plurality of grains improves at least one property of the additively manufactured aluminum alloy product (e.g., a strength property).

[0075] In one or more of the described embodiments, an additively manufactured aluminum alloy product has a solidus temperature (Ts), and the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (TH), where 0.8Ts < TH < Ts, (where TH and Ts are in Kelvin) (i.e., the additively manufactured product is heated to a temperature that is at least 80% of its solidus temperature, but lower than its solidus temperature). In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (TH), where 0.85Ts < TH < Ts. In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (T _H ), where 0.90Ts < T _H < Ts. In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (T _H ), where 0.95Ts < T _H < Ts. In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (TH), where 0.99Ts < TH < TS.

[0076] In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (TH), where 0.8Ts < TH £ 0.99Ts (i.e., the additively manufactured product is heated to a temperature in the range from 80% of its solidus temperature to not greater than 99% of its solidus temperature). In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (TH), where 0.85Ts < TH £ 0.99TS. In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (T _H ), where 0.90Ts < T _H £ 0.99Ts. In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (TH), where 0.95Ts < TH £ 0.99Ts. In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (T _H ) that is 0.99Ts.

[0077] The heating (120) to the heating temperature (T _H ) may comprise heating at least a portion of the additively manufactured aluminum alloy product to one or more temperatures and for any suitable duration, so long as at least the area weighted average grain size of the first plurality of grains increases, as provided herein (see Section b.v, below).

[0078] As used herein, the term“solidus” temperature means the temperature below which a product is completely solid.

[0079] In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (T _H ), where T _H £ 0.85TS (i.e., the additively manufactured product is heated to a temperature that is not greater than 85% of its solidus temperature). In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (T _H ), where T _H £ 0.90TS. In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (T _H ), where T _H £ 0.95TS. In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (TH), where TH £ 0.99TS.

[0080] In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (TH), where 0.8Ts < TH £ 0.95Ts. In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured product to a heating temperature (TH), where 0.8Ts < TH £ 0.95Ts. In one or more of the described embodiments, the heating (120) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (T _H ), where 0.90Ts < T _H £ 0.95T _S .

[0081] Generally, the heating (120) comprises heating the additively manufactured aluminum alloy product to a temperature and for a time sufficient to achieve the area weighted average grain size differences described herein (e.g., at Section b.v). Any suitable heating duration may be used. In one or more of the described embodiments, the heating (120) comprises heating for 0.1 hour to 100 hours. In one or more of the described embodiments, the heating (120) comprises heating for 1 hour to 100 hours. In one or more of the described embodiments, the heating (120) comprises heating for 5 hours to 100 hours. In one or more of the described embodiments, the heating (120) comprises heating for 10 hours to 100 hours. In one or more of the described embodiments, the heating (120) comprises heating for 30 hours to 100 hours. In one or more of the described embodiments, the heating (120) comprises heating for 50 hours to 100 hours. In one or more of the described embodiments, the heating (120) comprises heating for 80 hours to 100 hours. In one or more of the described embodiments, the heating (120) comprises heating for greater than 100 hours.

[0082] In one or more of the described embodiments, the heating (120) comprises heating for 0.1 hour to 80 hours. In one or more of the described embodiments, the heating (120) comprises heating for 0.1 hour to 50 hours. In one or more of the described embodiments, the heating (120) comprises heating for 0.1 hour to 30 hours. In one or more of the described embodiments, the heating (120) comprises heating for 0.1 hour to 10 hours. In one or more of the described embodiments, the heating (120) comprises heating for 0.1 hour to 5 hours. In one or more of the described embodiments, the heating (120) comprises heating for 0.1 hour to 1 hour.

[0083] In one or more of the described embodiments, the heating (120) comprises heating for 1 hour to 80 hours. In one or more of the described embodiments, the heating (120) comprises heating for 5 hours to 50 hours. In one or more of the described embodiments, the heating (120) comprises heating for 10 hours to 30 hours. In one or more of the described embodiments, the heating (120) comprises heating for 1 hour to 30 hours.

[0084] The cooling step (130) may be accomplished via any suitable method. In one or more of the described embodiments, the cooling step (130) comprises quenching. In one or more of the described embodiments, the cooling step comprises at least one of air quenching and liquid quenching. In one or more of the described embodiments, the cooling step comprises at least one of forced air cooling, fan cooling, and mist spray cooling.

[0085] Any suitable cooling rate may be used during the cooling step (130). For instance, in one embodiment the cooling rate is at least 0.6°C per second. In another embodiment, the cooling rate is at least 1.1 °C per second. In yet another embodiment, the cooling rate is at least

I .7 °C per second. In another embodiment the cooling rate is at least 2.2°C per second. In yet another embodiment, the cooling rate is at least 2.8°C per second. In another embodiment, the cooling rate is at least 5.6°C per second. In yet another embodiment the cooling rate is at least

I I . l°C per second. In another embodiment, the cooling rate is at least 28°C per second. In another embodiment, the cooling rate is at least 56 °C per second. In yet another embodiment the cooling rate is at least 278°C per second. In another embodiment, the cooling rate is at least 556°C per second. In another embodiment, the cooling rate is at least l389°C per second. In yet another embodiment the cooling rate is at least 2222°C per second. In another embodiment, the cooling rate is at least 2778°C per second.

[0086] In other embodiments, other cooling rates may be realized. For instance, in one embodiment, the cooling rate is not greater than 2778°C per second. In another embodiment the cooling rate is not greater than 2222°C per second. In yet another embodiment, the cooling rate is not greater than l389°C per second. In another embodiment, the cooling rate is not greater than 556°C per second. In another embodiment the cooling rate is not greater than 278°C per second. In another embodiment, the cooling rate is not greater than 56 °C per second. In another embodiment, the cooling rate is not greater than 28°C per second. In yet another embodiment the cooling rate is not greater than l l . l°C per second. In another embodiment, the cooling rate is not greater than 5.6°C per second. In yet another embodiment the cooling rate is not greater than 2.2°C per second. In another embodiment, the cooling rate is not greater than 2.8°C per second. In yet another embodiment, the cooling rate is not greater than 1.7 °C per second. In another embodiment, the cooling rate is not greater than 1.1 °C per second. In yet another embodiment the cooling rate is not greater than 0.6°C per second. The cooling rates discussed above, relative to the cooling step (130) should be measured over the temperature range of 232-399°C and at or near the thickest portion of the product. Accordingly, thinner products may realize higher cooling rates. Thicker products may realizer lower cooling rates.

[0087] In one or more of the described embodiments, prior to the heating (120), the method comprises machining at least a portion of the additively manufactured aluminum alloy product. v. Pre- and Post-Heat Treatment Grain Size

[0088] With continued reference to FIGS. 1-3, after the additive manufacturing (100), an additively manufactured aluminum alloy product may have a first plurality of grains. The first plurality of grains may realize a first area weighted average grain size. The heating (120) may comprise heating (120) the additively manufactured aluminum alloy product for a time and at a temperature sufficient to increase the first area weighted average grain size. Due to at least the heating (120) and the cooling (130) steps, a heat treated additively manufactured aluminum alloy product may be realized, the heat treated additively manufactured aluminum alloy product having a second plurality of grains. The second plurality of grains may realize a second area weighted average grain size (e.g., due to grain size changes of at least some of the first plurality of grains). It should be noted that while at least some grains of the first plurality of grains will change, in many instances some grains of the first plurality of grains will remain unchanged after the heating (120) and cooling (130) steps.

[0089] In one or more of the described embodiments, a ratio of the second area weighted average grain size (i.e., the area weighted average grain size of the heat treated additively manufactured aluminum alloy product) to the first area weighted average grain size (i.e., the area weighted average grain size of the additively manufactured aluminum alloy product) is at least 4. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is at least 5. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is at least 6. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is at least 7. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is at least 8. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is at least 9. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is at least 10.

[0090] In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 4 to 50. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 5 to 50. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 6 to 50. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 7 to 50. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 8 to 50. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 9 to 50. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 10 to 50. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 12 to 50. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 15 to 50. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 20 to 50. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 30 to 50. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 40 to 50. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 5 to 40. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 8 to 30. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 10 to 20. In one or more of the described embodiments, a ratio of the second area weighted average grain size to the first area weighted average grain size is from 12 to 15. [0091] In one or more of the described embodiments, an additively manufactured aluminum alloy product has a first plurality of grains, where the first plurality of grains has a first area weighted average grain size of less than 10 micrometers. In one or more of the described embodiments, a heat treated additively manufactured aluminum alloy product has a second plurality of grains, where the second plurality of grains has a second area weighted average grain size of at least 10 micrometers.

[0092] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 1 micrometers and a second plurality of grains has a second area weighted average grain size of at least 10 micrometers.

[0093] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 1.5 micrometers and a second plurality of grains has a second area weighted average grain size of at least 10 micrometers.

[0094] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 2 micrometers and a second plurality of grains has a second area weighted average grain size of at least 10 micrometers.

[0095] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 3 micrometers and a second plurality of grains has a second area weighted average grain size of at least 10 micrometers.

[0096] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 5 micrometers and a second plurality of grains has a second area weighted average grain size of at least 10 micrometers.

[0097] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 7 micrometers and a second plurality of grains has a second area weighted average grain size of at least 10 micrometers.

[0098] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 8 micrometers and a second plurality of grains has a second area weighted average grain size of at least 10 micrometers.

[0099] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 10 micrometers and a second plurality of grains has a second area weighted average grain size of at least 20 micrometers.

[0100] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 10 micrometers and a second plurality of grains has a second area weighted average grain size of at least 80 micrometers. [0101] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 10 micrometers and a second plurality of grains has a second area weighted average grain size of at least 100 micrometers.

[0102] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 10 micrometers and a second plurality of grains has a second area weighted average grain size of at least 120 micrometers.

[0103] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 10 micrometers and a second plurality of grains has a second area weighted average grain size of at least 150 micrometers.

[0104] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 10 micrometers and a second plurality of grains has a second area weighted average grain size of at least 200 micrometers.

[0105] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 10 micrometers and a second plurality of grains has a second area weighted average grain size of at least 250 micrometers.

[0106] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 10 micrometers and a second plurality of grains has a second area weighted average grain size of at least 300 micrometers.

[0107] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 10 micrometers and a second plurality of grains has a second area weighted average grain size of at least 350 micrometers.

[0108] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 10 micrometers and a second plurality of grains has a second area weighted average grain size of at least 400 micrometers.

[0109] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 100 micrometers and a second plurality of grains has a second area weighted average grain size of at least 450 micrometers.

[0110] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 10 micrometers and a second plurality of grains has a second area weighted average grain size of at least 500 micrometers.

[0111] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 3 micrometers and a second plurality of grains has a second area weighted average grain size of at least 50 micrometers. [0112] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 1.5 micrometers and a second plurality of grains has a second area weighted average grain size of at least 120 micrometers.

[0113] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 5 micrometers and a second plurality of grains has a second area weighted average grain size of at least 80 micrometers.

[0114] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of not greater than 8 micrometers and a second plurality of grains has a second area weighted average grain size of at least 125 micrometers.

[0115] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of 1 micrometers and a second plurality of grains has a second area weighted average grain size of 10 micrometers.

[0116] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of 3 micrometers and a second plurality of grains has a second area weighted average grain size of 50 micrometers.

[0117] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of 1.5 micrometers and a second plurality of grains has a second area weighted average grain size of 120 micrometers.

[0118] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of 5 micrometers and a second plurality of grains has a second area weighted average grain size of 80 micrometers.

[0119] In one or more of the described embodiments, a first plurality of grains has a first area weighted average grain size of 8 micrometers and a second plurality of grains has a second area weighted average grain size of 125 micrometers.

[0120] After the heating (120) and cooling (130) steps, a heat treated additively manufactured aluminum alloy product is realized. In some embodiments, the heat treated additively manufactured aluminum alloy product realizes at least one improved property, relative to the additively manufactured aluminum alloy product. The at least one improved property may be an improved fatigue property, an improved strength property, an improved fatigue crack growth property, an improved fracture toughness property, an improved corrosion resistance property, an improved creep property, and combinations thereof. In some embodiments, the improved corrosion resistance property is at least one of an improved stress corrosion cracking property, an improved intergranular corrosion resistance property, an improved galvanic corrosion resistance property, and an improved exfoliation corrosion susceptibility property. In one or more the described embodiments, the improved fracture toughness property is at least one of an improved plane-strain fracture toughness or an improved plane-stress fracture toughness. In one or more of the described embodiments, the improved strength property is at least one of an improved room temperature strength property and an improved elevated temperature strength property.

[0121] In one embodiment, the fatigue property is measured in accordance with ASTM E466, entitled,“Standard Practice for Conducting Force Controlled Constant Amplitude Axial Fatigue Tests of Metallic Materials”. Other fatigue properties may be tested / improved.

[0122] In one embodiment, the strength property may be at least one of a room temperature strength property and an elevated temperature strength property. Other strength properties may be tested / improved.

[0123] In one embodiment, the elevated temperature strength property is measured in accordance with ASTM E21, entitled,“Standard Test Methods for Elevated Temperature Tension Tests of Metallic Materials”.

[0124] In one embodiment, the room temperature strength property is measured in accordance with both ASTM E8, entitled,“Standard Test Methods for Tension Testing of Metallic Materials” and ASTM B557, entitled,“Standard Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products”.

[0125] In one embodiment, the fatigue crack growth is measured in accordance with ASTM E647, entitled,“Standard Test Method for Measurement of Fatigue Crack Growth Rates”. Other fatigue crack growth properties may be tested / improved.

[0126] In one embodiment, the fracture toughness property is at least one of a plane-strain fracture toughness or a plane-stress fracture toughness.

[0127] In one embodiment, the plane-strain fracture toughness is measured in accordance with ASTM E399, entitled,“Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness KIc of Metallic Materials”.

[0128] In one embodiment, the plane-stress fracture toughness is measured in accordance with both ASTM E561, entitled,“Standard Test Method for K-R Curve Determination” and ASTM B646 entitled,“Standard Practice for Fracture Toughness Testing of Aluminum Alloys”. [0129] In one embodiment, the creep property is measured in accordance with ASTM E139, entitled,“Standard Test Methods for Conducting Creep, Creep-Rupture, and Stress- Rupture Tests of Metallic Materials”. Other creep properties may be tested / improved.

[0130] As noted above, an improved corrosion resistance property may be at least one of an improved stress corrosion cracking property, an improved intergranular corrosion resistance property, an improved galvanic corrosion resistance property, and an improved exfoliation corrosion susceptibility property.

[0131] In one embodiment, the stress corrosion cracking property is measured in accordance with ASTM G47, entitled,“Standard Test Method for Determining Susceptibility to Stress-Corrosion Cracking of 2XXX and 7XXX Aluminum Alloy Products”. In another embodiment, the stress corrosion cracking property is measured in accordance with ASTM G44, entitled,“Standard Practice for Exposure of Metals and Alloys by Alternate Immersion in Neutral 3.5 % Sodium Chloride Solution”.

[0132] In one embodiment, the intergranular corrosion resistance property is measured in accordance with ASTM G110 entitled, “Standard Practice for Evaluating Intergranular Corrosion Resistance of Heat Treatable Aluminum Alloys by Immersion in Sodium Chloride + Hydrogen Peroxide Solution”.

[0133] In one embodiment, the galvanic corrosion resistance property is measured in accordance with ASTM G71, entitled, “Standard Guide for Conducting and Evaluating Galvanic Corrosion Tests in Electrolytes”.

[0134] In one embodiment, the exfoliation corrosion susceptibility property is measured in accordance with ASTM G34, entitled, “Standard Test Method for Exfoliation Corrosion Susceptibility in 2XXX and 7XXX Series Aluminum Alloys (EXCO Test)”.

[0135] In one or more of the described embodiments, a heat treated additively manufactured aluminum alloy product realizes at least two improved properties. In one or more of the described embodiments, a heat treated additively manufactured aluminum alloy product realizes at least three improved properties. In one or more of the described embodiments, a heat treated additively manufactured aluminum alloy product realizes at least four improved properties. In one or more of the described embodiments, a heat treated additively manufactured aluminum alloy product realizes at least five improved properties. In one or more of the described embodiments, a heat treated additively manufactured aluminum alloy product realizes at least six improved properties. In one or more of the described embodiments, a heat treated additively manufactured aluminum alloy product realizes at least seven improved properties.

vi. Optional Post-Heat Treatment Processing

[0136] With continued reference to FIGS. 1-3, after the additive manufacturing (100), optional deforming (110), heating (120), and cooling (130) steps, a heat treated additively manufactured aluminum alloy product may be optionally post processed (140).

[0137] In one or more of the described embodiments, the optional post processing (140) may comprise one or more deforming steps (141) (FIG. 2). The deforming (141) may be any of the deforming processes described above relative to the optional deforming step (110). In some embodiments, a heat treated additively manufactured aluminum alloy product is deformed, where the deforming comprises working. The working may include hot working and/or cold working. The working may include working all or a portion of the product. The working may include, for instance, rolling, extruding, forging, and other known methods of working aluminum alloy products. In one embodiment, the working comprises die forging the heat treated additively manufactured product into the final worked product, wherein the final worked product is a complex shape (e.g., having a plurality of non-planar surfaces).

[0138] In one or more of the described embodiments, the optional post-processing (140) may comprise aging (142) a heat treated additively manufactured aluminum alloy product. Aging (142) (e.g., natural aging, artificial aging) may facilitate the precipitation of one or more hardening phases from such supersaturated solutions (e.g., supersaturated solutions realized from a solution heat treatment). In one or more of the described embodiments, a method comprises aging (142) the heat treated additively manufactured aluminum alloy product to produce an aged additively manufactured aluminum alloy product, wherein the aging comprises aging a sufficient amount to realize at least one of a mechanical property and a machinability property that is improved compared to the heat treated additively manufactured aluminum alloy product (e.g., before the aging (142)). In one or more of the described embodiments, a method comprises aging (142) the additively manufactured aluminum alloy product at a lower temperature than the heating (120) temperature. In one or more of the described embodiments, an aged additively manufactured aluminum alloy product is cooled from the aging temperature and optionally subjected to one or more post processing steps such as working. In one or more of the described embodiments, an aging step (142) is conducted on an additively manufactured aluminum alloy product comprising a heat treatable alloy such as a 2xxx, 6xxx, 7xxx, or 8xxx series alloy. In one embodiment, the aging (142) comprises artificial aging by heating the product to a temperature of from l75°F to 450°F. Single-step or multiple-step aging practices may be used.

[0139] In one or more of the described embodiments, the optional post-processing (140) may comprise surface treating (143) a heat treated additively manufactured aluminum alloy product. Non-limiting examples of surface treating (143) includes anodizing, dyeing and/or painting, sealing via a sealant, surface polishing, surface patterning, and/or surface roughening.

[0140] In one embodiment, and now with reference to FIG. 12, a method (1200) may comprise additively manufacturing an aluminum alloy product (1201), heating the additively manufactured aluminum alloy product (1210), cooling the additively manufactured aluminum alloy product (1220), and aging (1230) (e.g., artificial, natural) the additively manufactured aluminum alloy product.

[0141] The method (10) may include producing a crack-free additively manufactured aluminum alloy product. In one or more of the described embodiments, an additively manufactured product is a crack-free product. In some embodiments,“crack-free” means that a product is sufficiently free of cracks such that it can be used for its intended, end-use purpose. The determination of whether a product is“crack-free” may be made by any suitable method, such as, by visual inspection, dye penetrant inspection, and/or by non-destructive test methods. In some embodiments, the non-destructive test method is an ultrasonic inspection. In some embodiments, the non-destructive test method is a computed topography scan (“CT scan”) inspection (e.g., by measuring density differences within the product). In one embodiment, an aluminum alloy product is determined to be crack-free by visual inspection. In another embodiment, an aluminum alloy product is determined to be crack-free by dye penetrant inspection. In yet another embodiment, an aluminum alloy product is determined to be crack- free by CT scan inspection. In another embodiment, an aluminum alloy product is determined to be crack-free during an additive manufacturing process, wherein in situ monitoring of the additively manufactured build is employed.

c. Product Applications

[0142] The additively manufactured aluminum alloy products described herein may be used in a variety of product applications. In one embodiment, the additively manufactured aluminum alloy products are utilized in an elevated temperature application, such as in an aerospace (e.g. engines or structures), automotive vehicle (e.g. piston, valve, among others), defense, electronics (e.g. consumer electronics) or space applications. In one embodiment, an additively manufactured aluminum alloy product is used in a ground transportation application. In one embodiment, an additively manufactured aluminum alloy product is utilized as an engine component in an aerospace vehicle (e.g., in the form of a blade, such as a compressor blade incorporated into the engine). In another embodiment, the additively manufactured aluminum alloy product is used as a heat exchanger for the engine of the aerospace vehicle. The aerospace vehicle including the engine component / heat exchanger may subsequently be operated. In one embodiment, an additively manufactured aluminum alloy product is an automotive engine component. The automotive vehicle including the engine component may subsequently be operated. For instance, an aluminum alloy product may be used as a turbocharger component (e.g., a compressor wheel of a turbocharger, where elevated temperatures may be realized due to recycling engine exhaust back through the turbocharger), and the automotive vehicle including the turbocharger component may be operated. In another embodiment, an additively manufactured aluminum product may be used as a blade in a land based (stationary) turbine for electrical power generation, and the land based turbine included the aluminum product may be operated to facilitate electrical power generation.

[0143] In another aspect, the new additively manufactured aluminum alloy products are utilized in a structural application. In one embodiment, the new additively manufactured aluminum alloy products are utilized in an aerospace structural application. For instance, the new additively manufactured aluminum alloy products may be formed into various aerospace structural components, including floor beams, seat rails, fuselage framing, bulkheads, spars, ribs, longerons, and brackets, among others. In another embodiment, the new additively manufactured aluminum alloy products are utilized in an automotive structural application. For instance, the new additively manufactured aluminum alloy products may be formed into various automotive structural components including nodes of space frames, shock towers, and subframes, among others.

[0144] Aside from the applications described above, the new additively manufactured aluminum alloy products of the present disclosure may also be utilized in a variety of consumer products, such as any consumer electronic products, including laptops, cell phones, cameras, mobile music players, handheld devices, computers, televisions, microwave, cookware, washer/dryer, refrigerator, sporting goods, or any other consumer electronic product requiring durability and selective visual appearance. In one embodiment, the visual appearance of the consumer electronic product meets consumer acceptance standards.

[0145] In some embodiments, the new additively manufactured aluminum alloy products of the present disclosure may be utilized in a variety of products including non-consumer products including the likes of medical devices, transportation systems and security systems, to name a few. In other embodiments, the new additively manufactured aluminum alloy products may be incorporated in goods including the likes of car panels, media players, bottles and cans, office supplies, packages and containers, among others.

d. Miscellaneous

[0146] While the disclosure generally relates to aluminum alloy products produced via additive manufacturing, in some embodiments, one or more of the aluminum alloy compositions (described below) may also find utility as ingot, casting alloys and/or wrought alloys. Thus, the present patent application also relates to ingot, casting alloys and wrought alloys made from the above-described aluminum alloy compositions. Indeed, the new products described herein may be produced by any other processes capable of generating solidification rates sufficient to impart one or more of the microstructural features. For instance, some continuous casting processes, such as those described in U.S. Patent No. 7, 182,825, may be capable of sufficiently high solidification rates, and the disclosure of this patent is incorporated herein by reference in its entirety.

[0147] The figures constitute a part of this specification and include illustrative embodiments of the present disclosure and illustrate various objects and features thereof. In addition, any measurements, specifications and the like shown in the figures are intended to be illustrative, and not restrictive. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0148] Among those benefits and improvements that have been disclosed, other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying figures. Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely illustrative of the invention that may be embodied in various forms. In addition, each of the examples given in connection with the various embodiments of the invention is intended to be illustrative, and not restrictive.

[0149] Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases“in one embodiment” and“in some embodiments” as used herein do not necessarily refer to the same embodiment(s), though it may. Furthermore, the phrases“in another embodiment” and“in some other embodiments” as used herein do not necessarily refer to a different embodiment, although it may. Thus, as described below, various embodiments of the invention may be readily combined, without departing from the scope or spirit of the invention.

[0150] In addition, as used herein, the term "or" is an inclusive "or" operator, and is equivalent to the term "and/or," unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meaning of "a," "an," and "the" include plural references, unless the context clearly dictates otherwise. The meaning of "in" includes "in" and "on", unless the context clearly dictates otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

[0151] FIG. 1 depicts a schematic flow chart of a non-limiting embodiment (10) of a method that includes additive manufacturing (100), optional deforming at least a portion of the additively manufactured aluminum alloy product (110), heating (120), cooling (130), and optional post-processing steps (140).

[0152] FIG. 2 depicts a schematic flow chart of a non-limiting embodiment (10) of a method that includes additive manufacturing (100), heating (120), cooling (130), and optional post processing (140) steps.

[0153] FIG. 3 depicts a schematic flow chart of a non-limiting embodiment (10) of a method that includes additive manufacturing (100) steps of selectively heating an additive manufacturing feedstock (101) to form a molten pool (104), cooling the molten pool (102) (e.g., via rapid solidification (105)), repeating (103) the heating the additive manufacturing feedstock (101) and cooling the molten pool steps (102) until an additively manufactured product is completed (106), followed by any of the heating (120), cooling (130) and optional post processing steps (140).

[0154] FIGS. 4 A, 4B, and 4C depict comparative Scanning Electron Microscope Electron Backscatter Diffraction (SEM-EBSD) images at the same magnification for each of Variant 1, Variant 2, and Variant 3 of Example 1 in the as-built condition at the same/corresponding test coupon location.

[0155] FIGS. 5A, 5B, and 5C depict comparative SEM-EBSD images for each of Variant 1, Variant 2, and Variant 3 of Example 1 at the same/corresponding test coupon location after heat treating. The heat treating included heating the samples to a temperature of 1020 degrees F. and holding at this temperature for 1 hour followed by cold water quenching, and then aging at 385 degrees Fahrenheit for 2 hours. FIGS. 5A, 5B and 5C include scale bars showing 100 micrometers, 20 micrometers and 100 micrometers, respectively. [0156] FIG. 6 depicts SEM-EBSD images for each of Variant 2 and Variant 3 of Example 1 at the same/corresponding test coupon location after subjecting the Variants to various heat treatment temperatures and times. FIG. 6 also shows the area weighted average grain size for each of Variant 2 and Variant 3 at the same/corresponding test coupon location after subjecting the Variants to various heat treatment temperatures and times.

[0157] FIG. 7 depicts SEM-EBSD images in the upper two images and images of anodized samples shown under polarized light in the lower twelve images. Images of the anodized samples are shown for each of Variant 2 and Variant 3 of Example 1 at the same/corresponding test coupon location after subjecting the Variants to various heating temperatures and times.

[0158] FIGS. 8A and 8B show the area weighted average grain size distributions for Variant 2 of Example 1 before and after heating to a temperature of 1020 degrees Fahrenheit and holding at this temperature for 1 hour, followed by cold water quenching and subsequent aging at 385 degrees Fahrenheit for 2 hours.

[0159] FIGS. 9A and 9B show the area weighted average grain size distributions for Variant 3 of Example 1 before and after heating to a temperature of 1020 degrees Fahrenheit and holding at this temperature for 1 hour, followed by cold water quenching and subsequent aging at 385 degrees Fahrenheit for 2 hours.

[0160] FIG. 10 depicts a chart detailing the tensile properties of Variants 1, 2, and 3 of Example 1 before and after heating to a temperature of 1020 degrees Fahrenheit and holding at this temperature for 1 hour, followed by cold water quenching and subsequent aging at 385 degrees Fahrenheit for 2 hours.

[0161] FIG. 11 depicts the fatigue evaluation of Variants 2 and 3 of Example 1 after heating to a temperature 1020 degrees Fahrenheit, holding at this temperature for 1 hour, followed by cold water quenching and subsequent aging at 385 degrees Fahrenheit for 2 hours.

[0162] FIG. 12 depicts a schematic flow chart of a non-limiting embodiment (1200) of a method that includes additive manufacturing (1201), heating (1210), cooling (1220), and aging (1230) steps.

DETAILED DESCRIPTION

[0163] Example 1

[0164] Table 1 shows the composition of the powders used to produce several experimental additively manufactured alloys (Variant 1, Variant 2 and Variant 3). The alloy compositions of the powders were measured using inductively coupled plasma spectrometry ("ICP").

Table 1: Measured Composition of Powders of Variants 1-3 (wt. %)

[0165] For each of the alloy variants, an increasing weight percent of grain refiner (TiB ₂ ) was utilized. Variant 1 included the lowest amount of grain refiner (0.19 wt. % TiB ₂ ), Variant 3 included the highest amount of grain refiner (2.6 wt. %), and Variant 2 included an intermediate amount of grain refiner (0.87 wt. %).

[0166] Three additively manufactured products were completed for each of Variants 1-3, utilizing a powder bed additive manufacturing machine (EOS M280). For each of the additively manufactured products, the layer thickness was approximately 35 micrometers, the hatch spacing was 0.19 mm, and the plate temperature was 200 degrees Celsius (392 degrees Fahrenheit). The same additive manufacturing product design was used for each of the additively manufactured products. Each additively manufactured product was used to produce test coupons to enable testing and evaluation on similar/corresponding portions of the each of the additively manufactured products. The additively manufactured products for Variants 1-3 were evaluated for their tendency to crack. The results are described below.

[0167] The Variant 1 additively manufactured products were observed to have cracks, based on visual inspection and CT scanning microscopy.

[0168] The Variant 2 additively manufactured products were not observed to have cracks, based on visual inspection and CT scanning microscopy.

[0169] The Variant 3 additively manufactured products were also not observed to be cracked, based on visual inspection and CT scanning microscopy. The microstructure of the Variant 3 additively manufactured products was observed to have finer grains and equiaxed grains, as compared to Variants 1 and 2.

[0170] After their production via additive manufacturing, Scanning Electron Microscope Electron Backscatter Diffraction (SEM-EBSD) micrographs of the variants were produced. FIGS. 4 A, 4B, and 4C depict comparative SEM-EBSD micrograph images at the same magnification for each of Variant 1, Variant 2, and Variant 3 at the same/corresponding test coupon location. The SEM-EBSD images depict the as-built grain structure of each of the Variants. Variant 1 (FIG. 4A) shows a grain structure where the grains have an aspect ratio of greater than 4: 1 and a substantially larger area weighted average grain size than Variants 2 (FIG. 4B) and 3 (FIG. 4C). Variant 2 (FIG. 4B) shows a generally equiaxed grain structure with a few areas of grain structure where the grains may have an aspect ratio of greater than 4: 1. Variant 3 (FIG. 4C) shows a grain structure that is equiaxed.

[0171] ETsing the procedure detailed herein, the area weighted average grain size was obtained from these SEM-EBSD images (FIGS. 4A-4C) for each variant. The measured area weighted average grain sizes were determined to be 25 micrometers for Variant 1, 3.9 micrometers for Variant 2, and 1.5 micrometers for Variant 3.

[0172] Each of the additively manufactured products for Variants 1, 2 and 3 were heated to and held at a temperature of 1020 degrees Fahrenheit for 1 hour, followed by cold water quenching. The additively manufactured products were then aged by heating the additively manufactured products to a temperature of 385 degrees Fahrenheit, where they were held for 2 hours. FIGS. 5A, 5B, and 5C depict comparative SEM-EBSD images for each of Variant 1, Variant 2, and Variant 3 at the same/corresponding test coupon location, after the heating, quenching, and aging steps. FIGS. 5A, 5B and 5C include scale bars showing 100 micrometers, 20 micrometers and 100 micrometers, respectively. Because of the very different grain sizes realized, the magnification of these SEM-EBSD images was varied, however, the scale bar in each image enables one to visually determine the approximate grain size.

[0173] ETsing the procedure for determining an area weighted average grain size given above, the area weighted average grain sizes were determined from the images shown in FIGS. 5 A-5C for each of the variants. After the heating, quenching, and aging steps described above, the area weighted average grain size of the additively manufactured products was 29.7 micrometers for Variant 1, 5.1 micrometers for Variant 2, and 124 micrometers for Variant 3. Without being bound by any mechanism or theory, the aging at 385 degrees Fahrenheit for 2 hours was not expected to affect area weighted average grain size of Variants 1, 2, and 3. Based on the area weighted average grain size results, the heat treatment was insufficient to substantially grow the grains in Variants 1 and 2. In contrast, after the heating, quenching and aging steps, Variant 3 realized a substantial grain growth from the as-built condition (1.5 micrometers), relative to the heat treated condition (124 micrometers). [0174] The additively manufactured products of Variants 2 and 3 were heated to various temperatures to determine their grain growth response at various temperatures. The additively manufactured products were heated to temperatures of 900 degrees F, 1020 degrees Fahrenheit and 1100 degrees Fahrenheit. Separate samples of the additively manufactured products were held at these temperatures for 1 hour and 10 hours. The solidus temperature for the alloy of Variants 2 and 3 is 1121 degrees F. After heating to 900, 1020, and 1100 degrees Fahrenheit for 1 or 10 hours, SEM-EBSD images of the heat treated additively manufactured products were obtained. ETsing the procedure detailed herein, the area weighted average grain size was obtained from SEM-EBSD images. FIG. 6 depicts SEM-EBSD images for each of Variant 2 and Variant 3 at the same test coupon location after subjecting Variants 2 and 3 temperatures of 900, 1020, and 1100 degrees Fahrenheit for 1 or 10 hours. Note that SEM-EBSD images were not obtained of Variant 2 at the following conditions: 900 degrees Fahrenheit for 1 hour and 1100 degrees Fahrenheit for 1 hour. Further, SEM-EBSD images were not obtained of variant 3 for the following conditions: 900 degrees Fahrenheit for 1 hour, 1100 degrees Fahrenheit for 1 hour, 1020 degrees Fahrenheit for 10 hours, and 1100 degrees Fahrenheit for 10 hours. Without being bound by any particular mechanism or theory, FIG. 6 shows that the smaller the starting grain size (e.g., having a higher grain boundary curvature), the higher the driving force for grain growth. Also, without being bound by any particular mechanism or theory, FIG. 6 shows that higher amounts of TiB ₂ grain refiner yields a smaller average grain size in the additively manufactured product (pre-heat treatment) which, in turn, provides a larger driving force for grain growth during heat treatment.

[0175] The additively manufactured products of Variants 2 and 3 described above that were subjected to temperatures of 900 degrees F, 1020 degrees Fahrenheit and 1100 degrees Fahrenheit for 1 hour and 10 hours were anodized. Images of each anodized sample were obtained under polarized light. FIG. 7 depicts SEM-EBSD images (the upper two images) and images of the anodized samples under polarized light (the lower twelve images) for each of Variant 2 and Variant 3. The anodized samples were evaluated at the same test coupon location after subjecting Variants 2 and 3 to the various temperatures (900, 1020, and 1100 degrees Fahrenheit) and times (1 hour and 10 hours). As shown in FIG. 7, after heat treatment at 900 degrees Fahrenheit for 1 hour and 10 hours, Variant 3 (after 10 hours) has a microstructure with only a few coarse grains compared to Variant 2 (after 1 and 10 hours) and Variant 3 (after 1 hour), both of which have microstructures with fine grains. As shown in FIG. 7, after heat treatment at 1020 degrees Fahrenheit for 1 hour and 10 hours, Variant 2 (after 10 hours) and Variant 3 (after 1 and 10 hours) show a microstructure having at least 20% of coarse grains, whereas Variant 2 (after 1 hour) shows a microstructure with predominantly fine grains. As shown in FIG. 7, after heat treatment at 1100 degrees Fahrenheit for 1 hour and 10 hours, the microstructures of Variants 2 and 3 have a majority of coarse grains.

[0176] The area weighted grain size distributions for Variants 2 and 3 before and after heating to 1020 degrees Fahrenheit and holding at this temperature for 1 hour, followed by a cold water quench and then aging at 385 degrees Fahrenheit for 2 hours are depicted in FIGS. 8A (Variant 2), 8B (Variant 2 - heat treated), 9A (Variant 3), and 9B (Variant 3 - heat treated). As noted above, without being bound by any mechanism or theory, the aging at 385 degrees Fahrenheit for 2 hours was not expected to affect the area weighted average grain size of Variants 2 and 3. As shown in FIGS. 8A and 8B, the heat treatment was insufficient to transform the average grain size distribution for Variant 2. In contrast, as shown in FIGS. 9A and 9B, the heat treatment transformed the average grain size distribution of Variant 3. Specifically, FIG. 9B shows about 97% of the microstructure of Variant 3 (after the heating and quenching) having grains of greater than 10 micrometers in size.

[0177] FIG. 10 depicts a chart detailing the tensile properties of Variants 1, 2, and 3 before and after heating to 1020 degrees Fahrenheit and holding at this temperature for 1 hour, followed by cold water quenching and subsequent aging at 385 degrees Fahrenheit for 2 hours. The tensile testing was conducted in accordance with ASTM E8 and ASTM B557. As depicted in Table 10, for the additive manufactured products (no heat treatment) (Variants 1, 2, and 3), the tensile yield strength increased with an increasing TiB ₂ content, and the ultimate tensile strength was relatively unaffected by TiB ₂ content. The ultimate tensile strength of the additively manufactured products for Variant 2 and 3 were almost the same due to their similar grain size (3.9 micrometers and 1.5 micrometers, respectfully). After heat treatment, the ultimate tensile strength of Variant 3 is about 3-5 ksi higher than Variant 2. While not being bound by any theory, it is believed that the improved ultimate tensile strength of variant 3 was realized as a result of the substantial increase in grain size after heat treatment.

[0178] FIG. 11 depicts the fatigue evaluation of Variants 2 and 3 after being heated to a temperature of 1020 degrees Fahrenheit and holding at this temperature for 1 hour, followed by cold water quenching and subsequent aging at 385 degrees Fahrenheit for 2 hours. The fatigue evaluation was conducted in accordance with ASTM E466. Notably, Variant 1 was cracked and thus, was not tested. Variant 3 showed the best performance particularly above the maximum stress level of 150 MPa. [0179] Additional Non-Limiting Embodiments

[0180] One or more of the embodiments of the instant disclosure includes the embodiments described in the following paragraphs.

[0181] In one embodiment, an additively manufactured aluminum alloy part is provided comprising at least 20% of the area of the microstructure having large equiaxed grains, wherein the large equiaxed grains have a grain size of at least 10 micrometers, and wherein the large equiaxed grains have an average aspect ratio of less than 4: 1.

[0182] In one or more of the described embodiments, at least 40% of the area of the micro structure has large equiaxed grains.

[0183] In one or more of the described embodiments, the area weighted average grain size is 10 micrometers to 500 micrometers.

[0184] In one or more of the described embodiments, the area weighted average grain size is 50 micrometers to 200 micrometers.

[0185] In one or more of the described embodiments, the large equiaxed grains have an average aspect ratio of less than 3 : 1.

[0186] In one or more of the described embodiments, the additively manufactured aluminum alloy part comprises a lxxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx, 8xxx, lxx, 2xx, 3xx, 4xx, 5xx, 7xx, 8xx or Al-Li series aluminum alloy.

[0187] In one or more of the described embodiments, the additively manufactured aluminum alloy part comprises 20% to 99% of the area of the microstructure having large equiaxed grains and a remainder of grains of the additively manufactured aluminum alloy part comprise at least one of (i) a grain size of less than 10 micrometers or (ii) an average aspect ratio of at least 4: 1.

[0188] In one embodiment, a method is provided, comprising heat treating an additively manufactured aluminum alloy part having a first area weighted average grain size for a sufficient time and a sufficient temperature to increase the average grain size of the additively manufactured aluminum alloy part to a second area weighted average grain size of at least 4 times that of the first area weighted average grain size, and cooling the heat treated additively manufactured aluminum alloy part, wherein the heat treated additively manufactured aluminum alloy part has improved properties as compared to a non-heat treated additively manufactured aluminum alloy part.

[0189] In one or more of the described embodiments, the method further comprises heat treating the additively manufactured aluminum alloy part having the first area weighted average grain size for the sufficient time and the sufficient temperature to increase the average grain size of the additively manufactured aluminum alloy part to the second area weighted average grain size of at least 5 times that of the first area weighted average grain size.

[0190] In one embodiment, a method is provided, comprising heat treating an additively manufactured aluminum alloy part having a first area weighted average grain size of less than 10 micrometers for a sufficient time and a sufficient temperature to increase the first area weighted average grain size of the additively manufactured aluminum alloy part to form a heat treated additively manufactured aluminum alloy part comprising at least 20% of the area of the microstructure having large equiaxed grains, wherein the large equiaxed grains have a grain size of at least 10 micrometers, and wherein the large equiaxed grains have an average aspect ratio of less than 4: 1, and cooling the heat treated additively manufactured aluminum alloy part, wherein the heat treated additively manufactured aluminum alloy part has improved properties as compared to a non-heat treated additively manufactured aluminum alloy part.

[0191] In one embodiment, a method is provided, comprising (a) selectively heating at least a portion of an additive manufacturing feedstock to a temperature above a liquidus temperature of the additive manufacturing feedstock to form a molten pool, wherein the additive manufacturing feedstock comprises an aluminum alloy portion and a grain refiner portion, thereby forming a molten pool, (b) cooling the molten pool, thereby forming a solidified mass, (c) repeating steps (a)-(b), thereby producing an additively manufactured aluminum alloy part, wherein the additively manufactured aluminum alloy part comprises a area weighted average grain size of not greater than 10 micrometers, and (d) heat treating the additively manufactured aluminum alloy part to a sufficient temperature and sufficient time to form a heat treated additively manufactured aluminum alloy part comprising at least 20% of the area of the microstructure having large equiaxed grains, wherein the large equiaxed grains have a grain size of at least 15 micrometers, and wherein the large equiaxed grains have an average aspect ratio of less than 4: 1.

[0192] In one or more of the described embodiments, the method further comprises heating at least a portion of the additively manufactured aluminum alloy part to at least 80% of the solidus temperature of the additively manufactured aluminum alloy part.

[0193] In one or more of the described embodiments, the method further comprises heating at least a portion of the additively manufactured aluminum alloy part to at least 80% of the solidus temperature of the additively manufactured aluminum alloy part for 0.1 to 100 hours. [0194] In one or more of the described embodiments, the method comprises improvement in properties that are evaluated using at least one of: ASTM E399, ASTM E466, ASTM E647, ASTM G47, ASTM G44, ASTM E139, ASTM Gl 10, ASTM G71, ASTM G34, ASTM E8 or ASTM B557.

[0195] In one or more of the described embodiments, the method comprises improvement in properties selected from at least one of: fracture toughness measured in accordance with ASTM E399, fatigue measured in accordance with ASTM E466, fatigue crack growth measured in accordance with ASTM E647, stress corrosion cracking as measured in accordance with ASTM G47 and/or ASTM G44, creep as measured in accordance with ASTM E139, corrosion as measured by (e.g. intergranular, galvanic/general corrosion, exfoliation corrosion, as measured in accordance with ASTM G110, ASTM G71 and/or ASTM G34, or strength as measured in accordance with ASTM E8 or ASTM B557.

[0196] In one or more of the described embodiments, the heat treating step comprises solution heat treating or annealing.

[0197] In one or more of the described embodiments, the method further comprises cooling the molten pool step at a cooling rate of at least 1,000 degrees Celsius per second.

[0198] In some embodiments, the cooling step comprises quenching.

[0199] In some embodiments, the cooling step comprises at least one of air quenching or liquid quenching.

[0200] In one or more of the described embodiments, the additive manufacturing feedstock comprises a sufficient amount of the grain refiner portion to form an additively manufactured aluminum alloy part comprising an area weighted average grain size of no greater than 10 micrometers.

[0201 ] In one or more of the described embodiments, the additive manufacturing feedstock comprises 0.1 weight percent to 6 weight percent of the grain refiner portion.

[0202] In one or more of the described embodiments, the aluminum alloy portion comprises a lxxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx, 8xxx, lxx, 2xx, 3xx, 4xx, 5xx, 7xx,

8xx or Al-Li series aluminum alloy.

[0203] In one or more of the described embodiments, prior to the heat treating step, the method comprises deforming at least a portion of the additively manufactured aluminum alloy part.

[0204] In one or more of the described embodiments, the deforming comprises at least one of shot peening, grit blasting or laser shot peening. [0205] In one or more of the described embodiments, prior to heat treating, the method comprises machining at least a portion of the additively manufactured aluminum alloy part.

[0206] In one or more of the described embodiments, the method comprises surface treating the additively manufactured aluminum alloy part.

[0207] In one or more of the described embodiments, the method comprises aging the additively manufactured aluminum alloy part sufficiently such that at least one of: a mechanical property or machinability is improved compared to a non-aged additively manufactured aluminum alloy part.

[0208] Clauses

[0209] Aspects of the invention will now be described with reference to the following numbered clauses:

Clause 1. An additively manufactured aluminum alloy product comprising:

a plurality of grains:

wherein the plurality of grains comprise large equiaxed grains;

wherein the large equiaxed grains have an area weighted average grain size of greater than 10 micrometers and an average aspect ratio of less than 4: 1; and

wherein at least 20% of the plurality of grains are large equiaxed grains.

Clause 2. The additively manufactured aluminum alloy product of clause 1, wherein at least 40% of the plurality of grains are large equiaxed grains.

Clause 3. The additively manufactured aluminum alloy product of any of the preceding clauses, wherein an area weighted average grain size of the plurality of grains is not greater than 500 micrometers.

Clause 4. The additively manufactured aluminum alloy product of any of the preceding clauses, wherein an area weighted average grain size of the plurality of grains is at least 50 micrometers, or at least 100 micrometers, or at least 150 micrometers, or at least 200 micrometers.

Clause 5. The additively manufactured aluminum alloy product of any of the preceding clauses, wherein an area weighted average grain size of the plurality of grains is not greater than 450 micrometers, or not greater than 400 micrometers, or not greater than 350 micrometers, or not greater than 300 micrometers, or not greater than 250 micrometers. Clause 6. The additively manufactured aluminum alloy product of any of the preceding clauses, wherein the plurality of grains comprises (i) the large equiaxed grains and (ii) remainder grains, wherein:

(a) not greater than 99% of the plurality of grains are large equiaxed grains;

(b) at least 1% of the plurality of grains are remainder grains, wherein the remainder grains realize at least one of:

(i) a grain size of not greater than 10 micrometers; and

(ii) an average aspect ratio of at least 4: 1.

Clause 7. A method comprising:

(a) heating an additively manufactured aluminum alloy product having a first plurality of grains;

wherein prior to the heating, the first plurality of grains have a first area weighted average grain size;

wherein the heating comprises heating the additively manufactured aluminum alloy product for a time and at a temperature sufficient to increase the first area weighted average grain size;

(b) cooling the additively manufactured aluminum alloy product, wherein, at least due to the heating and cooling steps a heat treated additively manufactured aluminum alloy product is realized;

wherein the heat treated additively manufactured aluminum alloy product comprises a second plurality of grains;

wherein the second plurality of grains has a second area weighted average grain size;

wherein, relative to the additively manufactured aluminum alloy product, the heat treated additively manufactured aluminum alloy product realizes at least one of:

an improved fatigue property;

an improved strength property;

an improved fatigue crack growth property;

an improved fracture toughness property;

an improved corrosion resistance property, wherein the improved corrosion resistance property is at least one of an improved stress corrosion cracking property, an improved intergranular corrosion resistance property, an improved galvanic corrosion resistance property, and an improved exfoliation corrosion susceptibility property; and

an improved creep property.

Clause 8. The method of clause 7, wherein a ratio of the second area weighted average grain size to the first area weighted average grain size is at least 4, or at least 5.

Clause 9. The method of any of clauses 7-8, wherein the first area weighted average grain size is less than 10 micrometers.

Clause 10. The method of any of clauses 7-9, wherein the second plurality of grains comprises large equiaxed grains and at least 20% of the second plurality of grains are large equiaxed grains, wherein:

the large equiaxed grains have a grain size of greater than 10 micrometers; and the large equiaxed grains have an average aspect ratio of less than 4:1.

Clause 11. The method of any of clauses 7-10, wherein the additively manufactured aluminum alloy product has a solidus temperature (Ts), wherein the heating step (a) comprises heating at least a portion of the additively manufactured aluminum alloy product to a heating temperature (T _H ), wherein 0.8Ts < T _H < Ts, and wherein T _H and Ts are in Kelvin. Clause 12. The method of any of clauses 7-11, wherein the heating step (a) comprises heating for 0.1 to 100 hours.

Clause 13. The method of any of clauses 7-12, wherein the cooling step (b) comprises quenching the additively manufactured aluminum alloy product.

Clause 14. The method of any of clauses 7-13, wherein prior to the heating step (a), the method comprises additively manufacturing the additively manufactured aluminum alloy product, wherein the additively manufacturing comprises:

selectively heating at least a portion of an additive manufacturing feedstock to a temperature above a liquidus temperature of the additive manufacturing feedstock, thereby forming a molten pool;

cooling the molten pool, thereby forming a solidified mass; and

repeating the selectively heating step and the cooling the molten pool step until the additively manufactured aluminum alloy product is completed.

Clause 15. The method of clause 14, wherein cooling the molten pool comprises cooling the molten pool at a cooling rate of at least 1,000 degrees Celsius per second, or at least 10,000 degrees Celsius per second, or at least 100,000 degrees Celsius per second, or at least 1,000,000 degrees Celsius per second. Clause 16. The method of any of clauses 14-15, wherein the additive manufacturing feedstock comprises aluminum and at least one grain refiner.

Clause 17. The method of clause 16, wherein the first area weighted average grain size is not greater than 10 micrometers, and wherein the additive manufacturing feedstock comprises a sufficient amount of the at least one grain refiner to realize the first area weighted average grain size of not greater than 10 micrometers.

Clause 18. The method of any of clauses 16-17, wherein the additive manufacturing feedstock comprises from 0.1 to 6 weight percent of the at least one grain refiner.

Clause 19. The method of any of clauses 16-18, wherein the additive manufacturing feedstock comprises an aluminum alloy, and wherein the aluminum alloy is selected from the group consisting of lxxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx, and 8xxx aluminum alloys. Clause 20. The method of any of clauses 7-19, wherein the method comprises machining at least a portion of the heat treated additively manufactured aluminum alloy product.

Clause 21. The method of any of clauses 7-20, wherein the method comprises aging the heat treated additively manufactured aluminum alloy product to produce an aged additively manufactured aluminum alloy product, wherein the aging comprises aging a sufficient amount to realize at least one of a mechanical property and a machinability property that is improved compared to the heat treated additively manufactured aluminum alloy product.

[0210] Other clauses based on any of the above paragraphs of the specification and the attached drawings are contemplated and apply to the present patent application.

[0211] While a number of embodiments of the present invention have been described, it is understood that these embodiments are illustrative only, and not restrictive, and that many modifications may become apparent to those of ordinary skill in the art. Further still, the various steps may be carried out in any desired order (and any desired steps may be added and/or any desired steps may be eliminated).