BACKGROUND

[001] Aluminum alloys are useful in a variety of applications. Aluminum alloy products are generally produced via either shape casting or wrought processes. Shape casting generally involves casting a molten aluminum alloy into its final form, such as via high pressure die, permanent mold, green and dry-sand, investment, or plaster casting. Wrought products are generally produced by casting a molten aluminum alloy into ingot or billet. The ingot or billet is generally further hot worked, sometimes with cold work, to produce its final form.

FIELD OF THE INVENTION

[002] The field of the invention relates to aluminum alloys having iron, silicon, and manganese, and methods for making the same.

SUMMARY OF THE INVENTION

[003] Broadly, the present disclosure relates to new aluminum alloys having iron, silicon, and manganese. The new aluminum alloy products described herein may realize an improved combination of properties, such as an improved combination of two or more of ductility, strength, thermal stability, creep resistance and fatigue failure resistance, among others. The new aluminum alloy products may be produced, for instance, via additive manufacturing.

i. Composition

[004] The new aluminum alloys described herein generally comprise (and in some instances consist of, or consist essentially of) 0.5 - 16.5 wt. % Fe, 0.5 - 16.5 wt. % Mn, 4 to 20 wt. % Si, not greater than 1.0 wt. % Cu, and where the total amount of iron plus manganese (i.e., the wt. % Fe plus wt. % Mn) is from 2.5 to 17 wt. %, the balance being aluminum, optional incidental elements, and impurities. Due to their composition and/or processing, the new aluminum alloys may realize an improved combination of properties, such as an improved combination of two or more of ductility, strength, thermal stability, creep resistance and fatigue failure resistance, among others. [005] As noted above, the new aluminum alloys generally comprise 4 to 20 wt. % silicon. Silicon may facilitate, for instance, reduced thermal shrinkage of the alloy. In one embodiment, an aluminum alloy comprises at least 4.5 wt. % Si. In another embodiment, an aluminum alloy comprises at least 5.0 wt. % Si. In yet another embodiment, an aluminum alloy comprises at least 5.5 wt. % Si. In one embodiment, an aluminum alloy comprises not greater than 18 wt. % Si. In another embodiment, an aluminum alloy comprises not greater than 17 wt. % Si. In yet another embodiment, an aluminum alloy comprises not greater than 16 wt. % Si. In another embodiment, an aluminum alloy comprises not greater than 15 wt. % Si. In yet another embodiment, an aluminum alloy comprises not greater than 14 wt. % Si. In another embodiment, an aluminum alloy comprises not greater than 13 wt. % Si.

[006] As noted above, the new aluminum alloys generally comprise 0.5 - 16.5 wt. % manganese. Manganese may facilitate, for instance, increased thermal stability of eutectic- type structures. In one embodiment, an aluminum alloy comprises at least 0.75 wt. % Mn. In another embodiment, an aluminum alloy comprises at least 1.0 wt. % Mn. In yet another embodiment, an aluminum alloy comprises at least 1.5 wt. % Mn. In another embodiment, an aluminum alloy comprises at least 2.0 wt. % Mn. In yet another embodiment, an aluminum alloy comprises at least 2.5 wt. % Mn. In another embodiment, an aluminum alloy comprises at least 3.0 wt. % Mn. In yet another embodiment, an aluminum alloy comprises at least 3.5 wt. % Mn. In another embodiment, an aluminum alloy comprises at least 4.0 wt. % Mn. In yet another embodiment, an aluminum alloy comprises at least 4.5 wt. % Mn. In one embodiment, an aluminum alloy comprises not greater than 15 wt. % Mn. In another embodiment, an aluminum alloy comprises not greater than 13 wt. % Mn. In yet another embodiment, an aluminum alloy comprises not greater than 11 wt. % Mn. In another embodiment, an aluminum alloy comprises not greater than 9 wt. % Mn. In yet another embodiment, an aluminum alloy comprises not greater than 8 wt. % Mn. In another embodiment, an aluminum alloy comprises not greater than 7 wt. % Mn. In yet another embodiment, an aluminum alloy comprises not greater than 6 wt. % Mn.

[007] As noted above, the new aluminum alloys generally comprise 0.5 - 16.5 wt. % iron. Iron may facilitate, for instance, increased thermal stability of eutectic-type structures. In one embodiment, an aluminum alloy comprises at least 1.0 wt. % Fe. In another embodiment, an aluminum alloy comprises at least 1.5 wt. % Fe. In yet another embodiment, an aluminum alloy comprises at least 2.0 wt. % Fe. In another embodiment, an aluminum alloy comprises at least 2.5 wt. % Fe. In yet another embodiment, an aluminum alloy comprises at least 3.0 wt. % Fe. In another embodiment, an aluminum alloy comprises at least 3.5 wt. % Fe. In yet another embodiment, an aluminum alloy comprises at least 4.0 wt. % Fe. In another embodiment, an aluminum alloy comprises at least 4.5 wt. % Fe. In one embodiment, an aluminum alloy comprises not greater than 15 wt. % Fe. In another embodiment, an aluminum alloy comprises not greater than 13 wt. % Fe. In yet another embodiment, an aluminum alloy comprises not greater than 11 wt. % Fe. In another embodiment, an aluminum alloy comprises not greater than 9 wt. % Fe. In yet another embodiment, an aluminum alloy comprises not greater than 8 wt. % Fe. In another embodiment, an aluminum alloy comprises not greater than 7 wt. % Fe. In yet another embodiment, an aluminum alloy comprises not greater than 6 wt. % Fe.

[008] As noted above, the new aluminum alloys generally comprise a total amount of iron plus manganese (i.e., the wt. % Fe plus the wt. % Mn) of from 2.5 to 17 wt. %. The amount of iron plus manganese relates to the amount of Al-Fe-Si-Mn intermetallics in the alloy. In one embodiment, an aluminum alloy comprises a total amount of iron plus manganese of at least 3 wt. %. In another embodiment, an aluminum alloy comprises a total amount of iron plus manganese of at least 4 wt. %. In yet another embodiment, an aluminum alloy comprises a total amount of iron plus manganese of at least 5 wt. %. In another embodiment, an aluminum alloy comprises a total amount of iron plus manganese of at least 6 wt. %. In yet another embodiment, an aluminum alloy comprises a total amount of iron plus manganese of at least 7 wt. %. In another embodiment, an aluminum alloy comprises a total amount of iron plus manganese of at least 8 wt. %. In one embodiment, an aluminum alloy comprises a total amount of iron plus manganese of not greater than 16 wt. %. In another embodiment, an aluminum alloy comprises a total amount of iron plus manganese of not greater than 15 wt. %. In yet another embodiment, an aluminum alloy comprises a total amount of iron plus manganese of not greater than 14 wt. %. In another embodiment, an aluminum alloy comprises a total amount of iron plus manganese of not greater than 13 wt. %. In yet another embodiment, an aluminum alloy comprises a total amount of iron plus manganese of not greater than 12 wt. %. In another embodiment, an aluminum alloy comprises a total amount of iron plus manganese of not greater than 11 wt. %.

[009] The new aluminum alloys generally include iron plus manganese in the amounts described above. In one embodiment, the weight ratio of manganese-to-iron (i.e., the wt. % Mn divided by the wt. % Fe) in the new aluminum alloys is from 0.04: 1 to 30:1. In one embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of at least 0.06: 1. In another embodiment, an aluminum alloy comprises a weight ratio of manganese- to-iron of at least 0.08: 1. In yet another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of at least 0.10: 1. In another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of at least 0.25: 1. In yet another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of at least 0.50: 1. In another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of at least 0.75: 1. In yet another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of at least 1 : 1. In another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of at least 1.1 : 1. In yet another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of at least 1.2: 1. In another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of at least 1.3:1. In yet another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of at least 1.4: 1. In another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of at least 1.5: 1. In one embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of not greater than 30: 1. In another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of not greater than 25: 1. In yet another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of not greater than 20: 1. In another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of not greater than 15: 1. In yet another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of not greater than 10:1. In another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of not greater than 8: 1. In yet another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of not greater than 5: 1. In another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of not greater than 4: 1. In yet another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of not greater than 2: 1. In yet another embodiment, an aluminum alloy comprises a weight ratio of manganese-to-iron of not greater than 1.75 : 1.

[0010] As noted above, the new aluminum alloys generally comprise not greater than 1.0 wt. % Cu. Excessive copper may, for instance, decrease corrosion resistance. In one embodiment, an aluminum alloy comprises not greater than 0.75 wt. % Cu. In another embodiment, an aluminum alloy comprises not greater than 0.50 wt. % Cu. In yet another embodiment, an aluminum alloy comprises not greater than 0.25 wt. % Cu. [0011] The new aluminum alloys may include tolerable amounts of other elements, such as zinc and/or magnesium. In one embodiment, an aluminum alloy comprises not greater than 1.0 wt. % Zn. In another embodiment, an aluminum alloy comprises not greater than 0.75 wt. % Zn. In yet another embodiment, an aluminum alloy comprises not greater than 0.50 wt. % Zn. In another embodiment, an aluminum alloy comprises not greater than 0.25 wt. % Zn. In one embodiment, an aluminum alloy comprises not greater than 1.0 wt. % Mg. In another embodiment, an aluminum alloy comprises not greater than 0.75 wt. % Mg. In yet another embodiment, an aluminum alloy comprises not greater than 0.50 wt. % Mg. In another embodiment, an aluminum alloy comprises not greater than 0.25 wt. % Mg.

[0012] As noted above, the balance of the aluminum alloy is aluminum, any optional incidental elements, and impurities. As used herein,“incidental elements” includes casting aids and/or grain structure control materials (e.g., grain refiners), such as titanium, zirconium, and the like, that may be used in the aluminum alloy.

[0013] As used herein,“grain refiner” means a nucleant or nucleants that facilitates alloy crystal formation. As it relates to the present alloying systems, a grain refiner may facilitate, inter alia , formation of eutectic structures and/or primary phase solidification. Suitable grain refiners include ceramic materials, intermetallic materials, and combinations thereof, among others.

[0014] 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, T1B2, TiC, SiC, AI2O3, BC, BN, S1 ₃ N4, AI4C ₃ , 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, zirconium, scandium, and hafnium, optionally in elemental form, among others.

[0015] As noted above, the balance of the new aluminum alloys is generally aluminum, any optional incidental elements, and impurities. In one embodiment, an aluminum alloy comprises not greater than 1.0 wt. % of the impurities, and wherein the aluminum alloy comprises not greater than 0.33 wt. % of any one element of the impurities. In another embodiment, an aluminum alloy comprises not greater than 0.75 wt. % of the impurities, and wherein the aluminum alloy comprises not greater than 0.25 wt. % of any one element of the impurities. In yet another embodiment, an aluminum alloy comprises not greater than 0.50 wt. % of the impurities, and wherein the aluminum alloy comprises not greater than 0.17 wt. % of any one element of the impurities. In another embodiment, an aluminum alloy comprises not greater than 0.30 wt. % of the impurities, and wherein the aluminum alloy comprises not greater than 0.10 wt. % of any one element of the impurities. In yet another embodiment, a new aluminum alloy comprises not greater than 0.15 wt. % of the impurities, and wherein the aluminum alloy comprises not greater than 0.05 wt. % of any one element of the impurities. In another embodiment, an aluminum alloy comprises not greater than 0.10 wt. % of the impurities, and wherein the new aluminum alloy comprises not greater than 0.03 wt. % of any one element of the impurities.

ii. Microstructure

[0016] As noted above, the new aluminum alloys may realize an improved combination of properties. In combination with appropriate solidification rates (e.g., those obtained by additive manufacturing processes) unique microstructures may be realized, which unique micro structures may at least partially contribute to the achievement of the improved properties. For instance, the new aluminum alloy products may realize an improved combination of properties, such as an improved combination of two or more of ductility, strength, thermal stability, creep resistance and fatigue failure resistance, among others. The amount of iron, manganese, and silicon within the aluminum alloy product may be varied relative to the desired amount of solidification structures (i.e., Al-Fe-Si-Mn intermetallics, optionally with Si particles). In one embodiment, the amount of iron, manganese, and silicon contained within the aluminum alloy product is sufficient to provide for at least 10 vol. % of solidification structures, and up to 40 vol. %, or more, of solidification structures. In one embodiment, an aluminum alloy product having such solidification structures comprises a fine eutectic-type structure (defined below). The solidification structures may facilitate, inter alia , strength and strength retention (thermal stability) in elevated temperature applications (e.g., for aerospace and/or automotive applications). The amount and type of solidification structures in the aluminum alloy product may be determined by metallographically preparing a cross section through a final part, using a scanning electron microscope (SEM) with appropriate image analysis software to measure the area fraction of the solidification structures, and, if appropriate, supplemented by a transmission electron microscope (TEM) analysis of a foil of the final part with appropriate image analysis software. In one embodiment, the amount of iron, manganese, and silicon contained within the aluminum alloy product may be sufficient to provide for at least 15 vol. % of solidification structures. In another embodiment, the amount of iron, manganese, and silicon contained within the aluminum alloy product may be sufficient to provide for at least 20 vol. % of solidification structures. In yet another embodiment, the amount of iron, manganese, and silicon contained within the aluminum alloy product may be sufficient to provide for at least 25 vol. % of solidification structures. In one embodiment, the amount of iron, manganese, and silicon contained within the aluminum alloy product may be sufficient to provide for not greater than 35 vol. % of solidification structures.

[0017] As noted above, the new aluminum alloy products may comprise a fine eutectic- type structure. As used herein, a“fine eutectic-type structure” means an alloy microstructure having regularly dispersed solidification structures, and comprising at least one of spheroidal, cellular, lamellar, wavy, brick and other suitable structures. In one embodiment, a fine eutectic-type structure comprises at least two of spheroidal, cellular, lamellar, wavy, brick or other suitable structures. As noted above, the spheroidal, cellular, lamellar, wavy, brick and/or other suitable structures may comprise Al-Fe-Si-Mn intermetallic compounds, optionally with Si particles. These Al-Fe-Si-Mn intermetallic compounds, optionally with Si particles, may make up, for instance, 10-40 vol. % of the final additively manufactured aluminum alloy product. For instance, FIG. la illustrates spheroidal Al-Fe-Mn-Si intermetallics (10). While not being bound by any theory, the Al-Fe-Mn-Si intermetallics (10) shown in FIG. la are believed to have formed first from the liquid during solidification (i.e., are primary intermetallic compounds).

[0018] As used herein, “solidification structures” are structures that form during solidification of an aluminum alloy and that at least partially define the fine eutectic-type microstructure of the aluminum alloy. As it relates to the Al-Fe-Si-Mn alloys described herein, the solidification structures generally include Al-Fe-Si-Mn intermetallics, and may include Si particles.

[0019] As used herein,“Al-Fe-Si-Mn intermetallics” means intermetallic compounds having aluminum and at least one of iron, silicon, and manganese therein. Thus, the term“Al-Fe-Si- Mn intermetallics” includes Al-Fe compounds, Al-Mn compounds, Al-(Fe,Mn) compounds, and Al-(Fe,Mn)-Si compounds, among others. Some non-limiting examples of“Al-Fe-Si-Mn intermetallics” include, for instance, Ali ₃ Fe4, AbFe, Al ₆ Fe, Al ₆ Mn, Al ₆ (Fe, Mn), and Ali ₅ (Fe,Mn) ₃ Si _2.

[0020] As used herein,“Si particles” generally means particles comprising silicon, unless the context clearly indicates otherwise. Si particles may be comprised of the Si-diamond phase, among others.

[0021] As used herein, a“particle” generally means a minute fragment of matter, unless the context clearly indicates otherwise. Particles may be, for instance, Si particles that may be included in the fine eutectic-type structures of the Al-Fe-Si-Mn alloys described herein.

[0022] In one embodiment, an aluminum alloy product comprises a fine eutectic-type structure having an average spacing between eutectic structures (“average eutectic spacing”) of not greater than 5 micrometers. In another embodiment, the average eutectic spacing is not greater than 4 micrometers. In yet another embodiment, the average eutectic spacing is not greater than 3 micrometers. In another embodiment, the average eutectic spacing is not greater than 2 micrometers. In yet another embodiment, the average eutectic spacing is not greater than 1 micrometers. In another embodiment, the average eutectic spacing is not greater than 0.7 micrometers. In yet another embodiment, the average eutectic spacing is not greater than 0.4 micrometers. In another embodiment, the average eutectic spacing is not greater than 0.1 micrometers. Fine eutectic-type structures may facilitate production of final products having a large volume fraction of Al-Fe-Si-Mn intermetallics therein (e.g., having 10-40 vol. % of Al-Fe-Si-Mn intermetallics), for instance, in the as-built condition and/or after post-build processing (e.g., a thermal treatment or thermomechanical treatment, among others).

[0023] As used herein,“average eutectic spacing” means the average spacing between the eutectic structures of the product as determined by the“Heyn Lineal Intercept Procedure” method described in ASTM standard El 12-13, entitled, “Standard Test Methods for Determining Average Grain Size”, wherein the distance between eutectic structures is/are measured as opposed to the grains.

[0024] FIG. 2 is a micrograph of an aluminum alloy product having a fine eutectic-type structure. Although FIG. 2 is taken from commonly owned International Application No. PCT/US17/67979 entitled, “Aluminum Alloy Products Having Fine Eutectic-Type Structures, And Methods For Making the Same,” it is expected that the same types of fine eutectic-type structures will be produced using the alloys and manufacturing processes described herein. FIG. 2 illustrates various fine eutectic-type structures, including cellular (20), lamellar (22) and wavy (24) structures. Other fine eutectic-type structures may be realized. For instance, any combination of cellular (20), lamellar (22), and wavy (24) structures, among other structures, may be realized.

[0025] In some embodiments, an aluminum alloy comprises coarsened solidification structures. As used herein, “coarsened solidification structures” means solidification structures that have coarsened (e.g., due to thermal and/or thermomechanical processing). For instance, due to thermal and/or thermomechanical processing (“TMP”), at least some portions of a fine eutectic-type structure may coarsen, resulting in coarsened solidification structures. As one example, FIG. ld shows a comparison of FIGs. la and lc, and demonstrates the microstructural differences between an invention alloy before (FIG. la) and after (FIG. lc) having been exposed to a temperature of 300°C for 100 hours. In this illustrative example, spheroidal Al-Fe-Si-Mn intermetallics (10), and coarsened solidification structures (14) are shown. As illustrated, the thermal treatment generally coarsened the cellular structures (12) into fine coarsened spheroidized structures (14). In the provided micrographs, generally all of the spheroidized particles have a diameter of not greater than 100 nm. While the coarsened solidification structures shown in these figures are generally spheroidized Al-Fe-Si-Mn intermetallics, coarsened solidification structures may be present in other forms, including, without limitation, any form that is an intermediary between an as- solidified fine eutectic-type structure and a structure that comprises the coarsened solidification structures (e.g., in a thermally treated condition). The coarsened solidification structures may be of any of the Al-Fe-Si-Mn intermetallics and Si particles described above, among others, and may present in forms such as, but not limited to, spheroidized particles.

[0026] The new aluminum alloys described herein may realize a low volume fraction of large Al-Fe-Si-Mn intermetallics in the form of spheroidal particles (e.g., globular particles, oblong particles). Large Al-Fe-Si-Mn intermetallics may be detrimental to properties (e.g., damage tolerance properties), and may be less effective at strengthening the alloy than smaller Al-Fe- Si-Mn intermetallics. As used herein,“large Al-Fe-Si-Mn spheroidal particles” means Al-Fe- Si-Mn intermetallics in the form of spheroidal particles and having a size of at least 100 nanometers, and wherein a particle’s“size” is its maximum length in any dimension. For instance, an Al-Fe-Si-Mn spheroidal particle having a size of 103 nm in the“X-direction”, a size of 92 nm in the“Y-direction” and a size of 98.8 nm in the“Z-direction”, would be considered a“large Al-Fe-Si-Mn spheroidal particle” due to its size of 103 nm in the X- direction exceeding the threshold requirement of 100 nm. However, if the X-direction size of this particle were 95 nanometers, with the Y- and Z-direction sizes remaining unchanged, this particle would not be a“large Al-Fe-Si-Mn spheroidal particle” because no dimension exceeds the threshold requirement of 100 nm. In one embodiment, large Al-Fe-Si-Mn spheroidal particles are spheroidal particles having a size of at least 200 nanometers. In another embodiment, large Al-Fe-Si-Mn spheroidal particles are spheroidal particles having a size of at least 300 nanometers.

[0027] As noted above, the new aluminum alloys described herein may realize a low volume fraction of large Al-Fe-Si-Mn spheroidal particles. In one embodiment, an aluminum alloy product comprises not greater than 20 vol. % of large Al-Fe-Si-Mn spheroidal particles. In another embodiment, an aluminum alloy product comprises not greater than 15 vol. % of large Al-Fe-Si-Mn spheroidal particles. In another embodiment, an aluminum alloy product comprises not greater than 10 vol. % of large Al-Fe-Si-Mn spheroidal particles. In yet another embodiment, an aluminum alloy product comprises not greater than 8 vol. % of large Al-Fe-Si-Mn spheroidal particles. In another embodiment, an aluminum alloy product comprises not greater than 5 vol. % of large Al-Fe-Si-Mn spheroidal particles. In yet another embodiment, an aluminum alloy product comprises not greater than 3 vol. % of large Al-Fe- Si-Mn spheroidal particles.

[0028] As noted above, the aluminum alloy products may be produced using one or more incidental elements, such as one or more grain refiners (grain refmer(s)). In one embodiment, an aluminum alloy product comprises grain refmers(s). The grain refmer(s) may facilitate production of, for instance, crack-free additively manufactured aluminum alloy products and/or aluminum alloy products with improved mechanical properties (e.g., improved ductility). In one embodiment, the feedstock comprises a sufficient amount of the grain refmer(s) to facilitate production of a crack-free additively manufactured product. The grain refmer(s) may facilitate, for instance, production of an additively manufactured aluminum alloy product having generally equiaxed grains. However, excessive grain refmer(s) may decrease the strength of the additively manufactured aluminum alloy product. Thus, in one embodiment, a feedstock comprises a sufficient amount of grain refmer(s) to facilitate production of a crack-free additively manufactured aluminum alloy product, but the amount of grain refmer(s) in the aluminum-based product is limited so that the additively manufactured aluminum-based product retains its strength (e.g., tensile yield strength (TYS) and/or ultimate tensile strength (UTS)). For instance, the amount of grain refmer(s) may be limited such that the strength of a grain refiner-containing aluminum alloy product is close to the same aluminum alloy product having no grain refiners. In one embodiment, the strength of a grain refiner-containing aluminum alloy product is within 10 ksi of the same aluminum alloy product without the grain refmer(s). In another embodiment, the strength of a grain refiner-containing aluminum alloy product is within 8 ksi of the same aluminum alloy product without the grain refmer(s). In yet another embodiment, the strength of a grain refiner-containing aluminum alloy product is within 6 ksi of the same aluminum alloy product without the grain refmer(s). In yet another embodiment, the strength of a grain refiner-containing aluminum alloy product is within 4 ksi of the same aluminum alloy product without the grain refmer(s). In another embodiment, the strength of a grain refiner- containing aluminum alloy product is within 2 ksi of the same aluminum alloy product without the grain refmer(s). In yet another embodiment, the strength of a grain refiner- containing aluminum alloy product is within 1 ksi of the same aluminum alloy product without the grain refmer(s). In one embodiment, the strength of a grain refiner-containing aluminum alloy product is within 15% of the same aluminum without the grain refmer(s). In another embodiment, the strength of a grain refiner-containing aluminum alloy product is within 12% of the same aluminum alloy product without the grain refmer(s). In yet another embodiment, the strength of a grain refiner-containing aluminum alloy product is within 9% of the same aluminum alloy product without the grain refmer(s). In another embodiment, the strength of a grain refiner-containing aluminum alloy product is within 6% of the same aluminum alloy product without the grain refmer(s). In yet another embodiment, the strength of a grain refiner-containing aluminum alloy product is within 3% of the same aluminum alloy product without the grain refmer(s). In one embodiment, an additively manufactured aluminum alloy product comprises up to 5 wt. %, in total, of grain refmer(s). In one embodiment, an additively manufactured aluminum alloy product comprises 0.1 - 5 wt. %, in total, of grain refmer(s). In another embodiment, an additively manufactured aluminum alloy product comprises 0.5 - 3 wt. %, in total, of grain refmer(s). In another embodiment, an additively manufactured aluminum alloy product comprises 1 - 3 wt. %, in total, of grain refmer(s). The appropriate amount of grain refmer(s) may facilitate improved properties, such as increased strength, reduced segregation, reduced thermal and solidification shrinkage, and increased ductility, among others. Furthermore, the appropriate amount of grain refmer(s) may restrict and/or prevent cracking (e.g., during additive manufacturing). In one embodiment, an additively manufactured aluminum alloy product comprises grain refmer(s), wherein the grain refmer(s) comprise TiB _2.

[0029] 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. In one embodiment, an additively manufactured aluminum alloy part comprises equiaxed grains having an average aspect ratio of less than 4: 1. In one embodiment, an additively manufactured aluminum alloy part comprises equiaxed grains having an average aspect ratio of not greater than 3: 1. In one described embodiment, an additively manufactured aluminum alloy part comprises equiaxed grains having an average aspect ratio of not greater than 2: 1. In one embodiment, an additively manufactured aluminum alloy part comprises equiaxed grains having an average aspect ratio of not greater than 1.5: 1. In one embodiment, an additively manufactured aluminum alloy part comprises equiaxed grains having an average aspect ratio of not greater than 1.1 : 1. The amount (volume percent) of equiaxed grains in the additively manufactured product in the as-built condition may be determined by EBSD (electron backscatter diffraction) analysis of a suitable number of SEM micrographs of the additively manufactured product in the as-built condition. Generally at least 5 micrographs should be analyzed.

[0030] As used herein,“grain” takes on the meaning defined in ASTM El 12 §3.2.2, i.e., “the area within the confines of the original (primary) boundary observed on the two- dimensional plane of-polish or that volume enclosed by the original (primary) boundary in the three-dimensional object”.

[0031] As used herein, the“grain size” is calculated by the following equation:

. AAL

v/ = square root (— )

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

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

Grain size is determined based on a two-dimensional plane that includes the build direction of the additively manufactured product. [0032] As used herein, the“area weighted average grain size” is calculated by the following equation:

v-bar

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

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

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

[0033] As used herein, the“as-built condition” means the condition of the additively manufactured aluminum alloy product after production and absent of any subsequent mechanical, thermal or thermomechanical treatments.

[0034] Aluminum alloy products that comprise equiaxed grains may realize, for instance, improved ductility and/or strength, among others. In this regard, equiaxed grains may help facilitate the realization of improved ductility and/or strength, among others. In one embodiment, an additively manufactured aluminum alloy product comprises equiaxed grains, wherein the average grain size is of from 0.5 to 50 microns. Use of grain refiners may help facilitate production of additively manufactured products having equiaxed grains.

[0035] In one embodiment, an additively manufactured aluminum alloy product in the as- built condition comprises grains and at least 50 vol. % of the grains are equiaxed grains. In another embodiment, an additively manufactured aluminum alloy product in the as-built condition comprises at least 60 vol. % of equiaxed grains. In yet another embodiment, an additively manufactured aluminum alloy product in the as-built condition comprises at least 70 vol. % of equiaxed grains. In another embodiment, an additively manufactured aluminum alloy product in the as-built condition comprises at least 80 vol. % of equiaxed grains. In yet another embodiment, an additively manufactured aluminum alloy product in the as-built condition comprises at least 90 vol. % of equiaxed grains. In another embodiment, an additively manufactured aluminum alloy product in the as-built condition comprises at least 95 vol. % of equiaxed grains. In yet another embodiment, an additively manufactured aluminum alloy product in the as-built condition comprises at least 99 vol. % of equiaxed grains, or more.

[0036] As noted above, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is generally not greater than 100 microns. In one embodiment, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is not greater than 90 microns. In another embodiment, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is not greater than 80 microns. In yet another embodiment, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is not greater than 70 microns. In another embodiment, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is not greater than 60 microns. In yet another embodiment, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is not greater than 50 microns. In another embodiment, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is not greater than 40 microns. In yet another embodiment, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is not greater than 30 microns. In another embodiment, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is not greater than 20 microns. In yet another embodiment, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is not greater than 10 microns. In another embodiment, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is not greater than 5 microns. In yet another embodiment, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is not greater than 4 microns. In another embodiment, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is not greater than 3 microns. In yet another embodiment, the average grain size of the additively manufactured aluminum alloy product in the as-built condition is not greater than 2 microns, or less. In one embodiment, the grains are equiaxed grains. In another embodiment, the grains are columnar grains.

[0037] In some embodiments, the additively manufactured product is a crack-free product. In some embodiments,“crack-free” means that the 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 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, as evaluated in accordance with ASTM E1441. 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.

[0038] As noted above, the aluminum alloy products may include an amount of grain refmer(s) sufficient to facilitate production of crack-free additively manufactured products having equiaxed grains. In one embodiment, the grain refmer(s) make up 0.1 - 5 wt. %, in total, of a crack-free additively manufactured aluminum alloy product. In another embodiment, the grain refmer(s) make up 0.5 - 3 wt. %, in total, of a crack-free additively manufactured aluminum alloy product. In yet another embodiment, the grain refmer(s) make up 1 - 3 wt. %, in total, of a crack-free additively manufactured aluminum alloy product.

[0039] In some embodiments, the aluminum alloy products comprise columnar grains (defined below). In one embodiment, an aluminum alloy product is free of grain refmer(s), and comprises columnar grains.

[0040] As used herein,“columnar grains” means grains having an average aspect ratio of at least 4:1 as measured in the YZ and/or XZ planes, wherein the Z plane is the build direction. 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. In one embodiment, columnar grains have an average aspect ratio of at least 5:1. In another embodiment, columnar grains have an average aspect ratio of at least 6: 1. In yet another embodiment, columnar grains have an average aspect ratio of at least 7: 1. In another embodiment, columnar grains have an average aspect ratio of at least 8: 1. In yet another embodiment, columnar grains have an average aspect ratio of at least 9: 1. In another embodiment, columnar grains have an average aspect ratio of at least 10: 1.

[0041] The new aluminum alloys described herein may realize a narrow non-equilibrium freezing range (e.g., not greater than 600°F). A narrow non-equilibrium freezing range may restrict the temperature range of the semi-solid state. In this regard, the semi-solid state may induce temperature gradients and/or thermal stresses that may cause an aluminum alloy product to crack during production. Thus, a narrow non-equilibrium freezing range may facilitate the production of crack-free products. In one embodiment, an aluminum alloy product realizes a non-equilibrium freezing range of not greater than 600°F. In another embodiment, an aluminum alloy product realizes a non-equilibrium freezing range of not greater than 550°F. In yet another embodiment, an aluminum alloy product realizes a non equilibrium freezing range of not greater than 500°F. In another embodiment, an aluminum alloy product realizes a non-equilibrium freezing range of not greater than 450°F. In yet another embodiment, an aluminum alloy product realizes a non-equilibrium freezing range of not greater than 400°F. In another embodiment, an aluminum alloy product realizes a non equilibrium freezing range of not greater than 350°F.

[0042] As used herein,“non-equilibrium freezing range” means the solidification range calculated using the Scheil solidification model implemented in commercial software PANDAT®. The Scheil solidification range is the non-equilibrium freezing range (complete diffusion in the liquid; no diffusion in the solid).

iii. Processing

[0043] The new aluminum alloys may be made via any suitable processing route. In one embodiment, the new aluminum alloys are in a cast form such as in the form of an ingot or billet (e.g., for using in making atomized powders). In one embodiment, the processing route involves rapid solidification (e.g., to facilitate production of fine eutectic-type microstructures), such as high-pressure die casting and some continuous castings techniques. In one embodiment, the new aluminum alloys are additively manufactured, as described below. In one embodiment, the new aluminum alloys are in the form of powders or wires (e.g., for use in an additive manufacturing process).

Additive Manufacturing

[0044] The aluminum alloys described herein may be used in additive manufacturing to produce an additively manufactured aluminum alloy body. 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”. Additively manufactured aluminum alloy bodies may be manufactured via any appropriate additive manufacturing technique described in this ASTM standard, such as binder jetting, directed energy deposition, material extrusion, material jetting, powder bed fusion, or sheet lamination, among others. Any suitable feedstocks may be used, including one or more powders, one or more wires, and combinations thereof. In some embodiments the additive manufacturing feedstock is comprised of one or more powders. In some embodiments, the additive manufacturing feedstock is comprised of one or more wires. A ribbon is a type of wire.

[0045] 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 additively manufactured aluminum alloy body (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). In one embodiment, additive manufacturing process uses a LENS additive manufacturing system, or comparable system, available from OPTOMEC, 3911 Singer N.E., Albuquerque, NM 87109.

[0046] As one example, a feedstock, such as a powder or wire, comprising (or consisting essentially of) the Al, the Fe, the Mn, the Si, and any optional incidental elements and impurities, and within the scope of the compositions described above, may be used in an additive manufacturing apparatus to produce an additively manufactured aluminum alloy body. In some embodiments, the additively manufactured aluminum alloy body is a crack- free preform. The feedstock may be selectively heated above the liquidus temperature of the material, thereby forming a molten pool having the Al, the Fe, the Mn, the Si, and any optional incidental elements and impurities, followed by rapid solidification of the molten pool thereby forming an additively manufactured aluminum alloy product, generally with 10- 40% vol. % of solidification structures therein. The additively manufactured aluminum alloy product may realize a fine eutectic-type microstructure.

[0047] As noted above, additive manufacturing may be used to create, layer-by-layer, the aluminum alloy product. In one embodiment, a metal powder bed is used to create a tailored aluminum alloy product. As used herein a“metal powder bed” means a bed comprising a metal powder. During additive manufacturing, particles of the same or different compositions may melt (e.g., rapidly melt) and then solidify (e.g., in the absence of homogenous mixing). Thus, products having a homogenous or non-homogeneous microstructure may be produced. One embodiment of a method of making an additively manufactured aluminum alloy body may include (a) dispersing a powder comprising the Al, the Fe, the Mn, the Si, and any optional incidental elements and impurities, (b) selectively heating a portion of the powder (e.g., via a laser) to a temperature above the liquidus temperature of the particular body to be formed, (c) forming a molten pool having the Al, the Fe, the Mn, the Si, and any optional incidental elements and impurities, and (d) cooling the molten pool at a cooling rate of at least l000°C per second. In one embodiment, the cooling rate is at least l0,000°C per second. In another embodiment, the cooling rate is at least l00,000°C per second. In another embodiment, the cooling rate is at least l,000,000°C per second. Steps (a)-(d) may be repeated as necessary until the aluminum alloy body is completed, i.e., until the final additively manufactured aluminum alloy body is formed / completed. The final additively manufactured aluminum alloy body may be of a complex geometry, or may be of a simple geometry (e.g., in the form of a sheet or plate), and may comprise 10-40% vol. % of solidification structures therein, and may realize a fine eutectic- type microstructure. After or during production, an additively manufactured aluminum alloy product may be deformed (e.g., by one or more of rolling, extruding, forging, stretching, compressing).

[0048] The powders used to additively manufacture an aluminum alloy body may be produced by atomizing a material (e.g., an ingot or melt) of the new alloy aluminum alloys into powders of the appropriate dimensions relative to the additive manufacturing process to be used. As used herein,“powder” means a material comprising a plurality of particles. Powders may be used in a powder bed to produce a tailored alloy product via additive manufacturing. In one embodiment, the same general powder is used throughout the additive manufacturing process to produce an aluminum alloy product. For instance, the final tailored aluminum alloy product may comprise a single region / matrix produced by using generally the same metal powder during the additive manufacturing process. The final tailored aluminum alloy product may alternatively comprise at least two separately produced distinct regions. In one embodiment, different metal powder bed types may be used to produce the aluminum alloy product. For instance, a first metal powder bed may comprise a first metal powder and a second metal powder bed may comprise a second metal powder, different than the first metal powder. The first metal powder bed may be used to produce a first layer or portion of the alloy product, and the second metal powder bed may be used to produce a second layer or portion of the alloy product. As used in this paragraph, a“particle” means a minute fragment of matter having a size suitable for use in the powder of the powder bed (e.g., a size of from 5 microns to 100 microns). Particles may be produced, for example, via atomization. A shaving is a type of particle. [0049] The additively manufactured aluminum alloy body may be subject to any appropriate working steps. If employed, the working steps may be conducted on an intermediate form of the additively manufactured body and/or may be conducted on a final form of the additively manufactured body. In one embodiment, an additively manufactured body consists essentially of the Al, the Fe, the Mn, the Si, and any optional incidental elements and impurities, such as any of the material compositions described above.

[0050] In another embodiment, an aluminum alloy body is a preform for subsequent working. A preform may be an additively manufactured product. In one embodiment, a preform is of a near net shape product that is close to the final desired shape of the final product, but the preform is designed to allow for subsequent working to achieve the final product shape. Thus, the preform may worked such as by forging, rolling, extrusion, or hipping to produce an intermediate product or a final product, which intermediate or final product may be subject to any further appropriate working or thermal steps (e.g., stress relief), as described above, to achieve the final product. In one embodiment, the working comprises hot isostatic pressing (hipping) to compress the part. In one embodiment, an aluminum alloy preform may be compressed and porosity may be reduced. In one embodiment, the hipping temperature is maintained below the incipient melting point of the aluminum alloy preform. In one embodiment, the preform may be a near net shape product.

[0051] In one approach, electron beam (EB) or plasma arc techniques are utilized to produce at least a portion of the additively manufactured aluminum alloy body. Electron beam techniques may facilitate production of larger parts than readily produced via laser additive manufacturing techniques. In one embodiment, a method comprises feeding a small diameter wire (e.g., < 5 mm in diameter) of the new aluminum alloys described herein to the wire feeder portion of an electron beam gun. The wire may be of the compositions, described above. The electron beam (EB) heats the wire above the liquidus point of the body to be formed, followed by rapid solidification (e.g., at least l00°C per second) of the molten pool to form the deposited material. The wire could be fabricated by a conventional ingot process or by a powder consolidation process. These steps may be repeated as necessary until the final aluminum alloy body is produced. Plasma arc wire feed may similarly be used with the aluminum alloys disclosed herein. In one embodiment, not illustrated, an electron beam (EB) or plasma arc additive manufacturing apparatus may employ multiple different wires with corresponding multiple different radiation sources, each of the wires and sources being fed and activated, as appropriate to provide the aluminum alloy product. [0052] In another approach, a method may comprise (a) selectively spraying one or more metal powders of the new aluminum alloys described herein towards a building substrate, (b) heating, via a radiation source, the metal powders, and optionally the building substrate, above the liquidus temperature of the product to be formed, thereby forming a molten pool, (c) cooling the molten pool, thereby forming a solid portion of the product, wherein the cooling comprises cooling at a cooling rate of at least l00°C per second. In one embodiment, the cooling rate is at least l000°C per second. In another embodiment, the cooling rate is at least l0,000°C per second. The cooling step (c) may be accomplished by moving the radiation source away from the molten pool and/or by moving the building substrate having the molten pool away from the radiation source. Steps (a)-(c) may be repeated as necessary until the product is completed. The spraying step (a) may be accomplished via one or more nozzles, and the composition of the metal powders can be varied, as appropriate, to provide a tailored final aluminum alloy product. The composition of the metal powder being heated at any one time can be varied in real-time by using different powders in different nozzles and/or by varying the powder composition(s) provided to any one nozzle in real-time. The work piece can be any suitable substrate. In one embodiment, the building substrate is, itself, a metal product (e.g., an alloy product, such as any of the aluminum alloy products described herein.)

iv. Applications

[0053] As previously stated, the new materials described above may be suitable for elevated temperature applications. For instance, the new aluminum alloy bodies of the new aluminum alloys described herein may be suitable in aerospace and/or automotive applications. Non-limiting examples of aerospace applications may include heat exchangers and turbines. In one embodiment, a new aluminum alloy product is in the form of a compressor component (e.g., turbocharger impeller wheels). Non-limiting examples of automotive applications may include interior or exterior trim/appliques, pistons, valves, and/or turbochargers. Other examples include any components close to a hot area of the vehicle, such as engine components and/or exhaust components, such as the manifold.

[0054] Aside from the applications described above, the new aluminum alloy bodies 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.

[0055] In another aspect, the new aluminum alloy products are utilized in a structural application. In one embodiment, the new aluminum alloy products are utilized in an aerospace structural application. For instance, the new 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 aluminum alloy products are utilized in an automotive structural application. For instance, the new aluminum alloy products may be formed into various automotive structural components including nodes of space frames, shock towers, and subframes, among others. In one embodiment, a new aluminum alloy product is a body-in white (BIW) automotive product.

[0056] In another aspect, the new aluminum alloy products are utilized in an industrial engineering application. For instance, the new aluminum alloy products may be formed into various industrial engineering products, such as tread-plate, tool boxes, bolting decks, bridge decks, and ramps, among others.

[0057] In some embodiments, the new aluminum alloy bodies 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 aluminum alloy bodies may be incorporated in goods including the likes of car panels, media players, bottles and cans, office supplies, packages and containers, among others.

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] FIG. la is a scanning electron micrograph of Alloy 4 from Example 1 in the as re- melted condition.

[0059] FIG. lb is a scanning electron micrograph of Alloy 4 from Example 1 in a thermally exposed condition (230°C for 100 hours).

[0060] FIG. lc is a scanning electron micrograph of Alloy 4 from Example 1 in a thermally exposed condition (300°C for 100 hours).

[0061] FIG. ld is a side-by-side comparison of FIG. la and FIG. lc. [0062] FIG. 2 is a scanning electron micrograph of an alloy (not of the present disclosure) illustrating lamellar, wavy, and cellular structures of a eutectic-type structure.

PET ATT /ED DESCRIPTION

EXAMPLES

[0063] Four inventive experimental alloys (Alloys 1-4) were cast as book mold ingots. A portion of each ingot was then re-melted and solidified to simulate an additive manufacturing process. Additionally, coupons of a comparison alloy (Alloys 5a and 5b) were additively manufactured for comparison purposes. Compositions of the four experimental alloys and the comparison alloy were measured via ICP and are given in Table la, below. Furthermore, the non-equilibrium freezing range of each alloy was determined using the Scheil solidification model implemented in commercial software PANDAT®, the results of which are given in Table lb, below.

Table la: Composition of Experimental Alloys (in wt. %)

Table lb: Non-Equilibrium Freezing Range of Experimental Alloys

[0064] Multiple samples of Alloys 1-4 were re-melted using a laser to simulate a laser powder bed additive manufacturing process. In this regard, the solidification conditions employed in the re-melting facilitated solidification rates on the order of l,000,000°C/s. Following production of the re-melted samples, some of the samples were subjected to thermal exposure at 230°C for 100 hours (Condition (A)) and 300°C for 100 hours (Condition (B)). Microhardness of the re-melted experimental alloys was evaluated in the as re-melted condition, as well as various thermally treated conditions. Coupons of Alloy 5 were produced via powder bed additive manufacturing, and were evaluated in the as-built condition (Alloy 5a) and in a T6-type temper (Alloy 5b). Some of the Alloy 5 samples were subsequently thermal exposed to realize Condition (A) and Condition (B), and were then evaluated for microhardness. The T6-type temper for Alloy 5b was achieved by solution heat treating at 530°C for 20 hours, cold water quenching, and artificially aging at l80°C for 4 hours. Vickers microhardness measurements were performed in accordance with ASTM standards E384 and E92, the results of which are given in Table 2, below. The standard deviation (“STDev”) of the microhardness values given in Table 2 are the average of five measurements for each condition.

Table 2: Vickers Microhardness Values (in HV)

• Condition (A) = Thermally exposed to 230°C for 100 hours

• Condition (B) = Thermally exposed to 300°C for 100 hours

• * Alloys 1-4 were evaluated in the As re-melted condition, while Alloys 5a and 5b were evaluated in the As-built condition

[0065] As shown in Table 2, the inventive alloys (Alloys 1-4) realized higher microhardness than the non-inventive alloy 5a and 5b in all conditions. Further, the inventive alloys retained their as re-melted microhardness in Condition (A), whereas the comparison alloy (Alloy 5a and 5b) did not. The inventive alloys relative retention of microhardness between the as re-melted condition and thermally exposed conditions was greater than non- inventive Alloy 5 a and 5b.

[0066] Scanning electron micrographs of Alloy 4 in the as re-melted and thermally exposed conditions are given in FIGs. la-lc. In this regard, FIG. la shows Alloy 4 in the as re-melted condition, FIG. lb shows Alloy 4 after 100 hours of exposure to 230°C (Condition A), and FIG. lc shows Alloy 4 after 100 hours of exposure to 300°C (Condition B). FIG. la illustrates a micrograph of an as re-melted sample of Alloy 4 having a fine eutectic-type structure, additionally with spheroidal particles. The fine eutectic-type structure is predominately comprised of cellular structures. As shown in FIG. lb, after exposure of Alloy 4 to 230°C, the alloy microstructure is similar to the as re-melted microstructure, indicating that the alloy is stable at temperatures up to at least 230°C. As shown in FIG. lc, after exposure of Alloy 4 to 300°C, coarsened solidification structures formed such as the fine coarsened spheroidized structures (14) that may form via spheroidization of the eutectic-type structures.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.