METALLIC POWDER MIXTURE FOR BUILD-UP OR REPAIR

The invention relates to a composition of a nickel based alloy mixture which can be used for welding via especially liquid metal deposition or as a powder bed of an additive manufacturing method.

For a blade tip repair with Laser Metal Deposition (LMD) standard alloys Inconel 625 and Merl 72 are used.

The oxidation resistance of both alloys at high temperatures T > 1273K is not better than the base material Alloy247.

Therefore, aim of the invention is to overcome the problem described above.

The problem is solved by a material according to claim 1, a powder according to claim 13, a method according to claim 14 and a product according claim 16.

The invention disclosure deals with the Laser Metal Deposi tion using powder additive material.

This material mixture can preferably be used for blade tip repair with increased oxidation resistance in comparison to most currently used alloys.

The oxidation resistance of the developed material mixture is better than the base material Alloy247.

A braze material has always a melting point at least 10K, es pecially at least 20K lower than the nickel or cobalt based superalloy . The powder mixture can be preferably welded using a standard power cladding process or used for any alternative manufac turing process, especially like SLM or SLS .

Preferably additions of a binder or ceramic secondary particles are possible.

A standard heat treatment process for the base nickel based alloy is used for the subsequent brazing process.

The composition of the powder mixture is described as fol lowed in wt%:

a braze: 5% - 15%,

a NiCoCrAlY : 80% - 60%,

a Nickel based superalloy: 10% - 30%,

especially Alloy 247, wherein the melting point of the braze is at least 10K, especially 20K lower than the melting point of the nickel or cobalt based superalloy.

As melting point the solidus temperature or liquidus tempera ture can be choosen, but in the same manner for all constitu ents .

The mixture comprises, especially consists of 3 powders with different compositions.

The advantages are

• High oxidation resistant material made from standard powder alloys

• Standard welding process "powder cladding" can be used for blade tip build up welding

The metallic powder mixture comprises the nickel (Ni) base superalloy comprises (in wt%) :

especially consists of (in wt%) : Carbon (C) 0.05% - 0.20% especially 0.07% - 0.17%

Chromium (Cr) 8.0% - 23.0% especially 12.0% - 23.0%

Cobalt (Co) 8.0% - 19.0% especially 9.0% - 10.0% very especially 18.0% - 19.0%

Tungsten (W) 2.0% - 10.0% especially 2.0% - 4.5%

very especially 9.0% - 10.0%

Titanium (Ti) 0.6% - 5.0%

Aluminum (Al) 1.0% - 6.0%

optionally

Boron (B) 0.005% - 0.03% especially 0.006% - 0.015%

Molybdenum (Mo) 0.0% - 4.5%

especially 0.50% - 4.0%

Tantalum (Ta) 0.0% - 4.5%

especially 1.0% - 4.5%

Hafnium (Hf) 0.6% - 1.5%

Zirconium (Zr) 0.02% - 0.12%

Niobium (Nb) 0.5% - 1.0%

especially no Yttrium (Y) and/or

no Rhenium (Re) ,

remainder Nickel (Ni),

especially

the nickel (Ni) base superalloy comprises, especially consists of (in wt%) :

Nickel (Ni ) 61.6%

Carbon (C) 0.08%

Chromium (Cr) 8.25%

Cobalt (Co) 9.25%

Molybdenum (Mo) 0.50%

Tungsten (W) 9.50%

Titanium (Ti) 0.75%

Aluminum (Al) 5.55%

Boron (B) 0.02%

Tantalum (Ta) 3.20% Hafnium (Hf) 1.30%,

especially no Yttrium (Y) and/or

no Rhenium (Re) .

Preferably the nickel based super alloy is selected from alloy247, Inconel625, Rene 80 and/or Merl72, especially alloy247.

Inconel 625 comprises (in wt%) :

C 0.03-0.10%

Si < 0.5%

Mn < 0.5%

P < 0.020%

S < 0.015%

Ti < 0.40%

Cr 20.0-23.0%

Mo < 8.0-10.0%

Ni > 58.0%

Cu < 0.5%

Nb 3.15-4.15%

A1 < 0.4%

Fe < 5.0%

Co < 1.0%.

Rene 80 comprises (in wt%) :

Ni = 60.0%

Cr = 14.0%

Co = 9.5%

Ti = 5.0%

Mo = 4.0%

W = 4.0%

A1 = 3.0%

C = 0.17%

B = 0.015%

Zr = 0.03%. Merl 72 comprises (in wt%) :

47% Co

20% Cr

15% Ni

9.0% W

4.4% A1

3.0% Ta

1.1% Hf

0.35% C

0.2% Ti

0.04% Y.

The braze alloy comprises preferably especially consists of (in wt%) :

Nickel (Ni) 51.70% - 52.40% Chromium (Cr) 14.00% - 14.25% Cobalt (Co) 19.00% - 19.60% Aluminum (Al) 8.00% - 8.30% Tantalum (Ta) 0.55% - 0.75% Molybdenum (Mo) 0.09% - 0.12% Hafnium (Hf) 0.22% - 0.30% Tungsten (W) 1.60% - 2.20% Titanium (Ti) 0.70% - 1.10% Yttrium (Y) 0.18% - 0.22% Rhenium (Re) 0.90% - 1.10% Carbon (C) 0.10% - 0.20% Zirconium (Zr) 0.90% - 1.80%.

Especially the braze alloy comprises, especially consists of (in wt%) :

Nickel (Ni) 52.00%

Chromium (Cr) 14.00%

Cobalt (Co) 19.30%

Aluminum (Al) 8.10%

Tantalum (Ta) 0.65%

Molybdenum (Mo) 0.10% Hafnium (Hf) 0.25%

Tungsten (W) 1.90%

Titanium (Ti) 0.90%

Yttrium (Y) 0.21%

Rhenium (Re) 1.05%

Carbon (C) 0.20%

Zirconium (Zr) 1.35%.

The melt depressant Zirconium (Zr) in the braze alloy is at least partially replaced by or it is additionally added:

Silicon (Si) and/or Magnesium (Mg) and/or Mangan (Mn) .

NiCoCrAlY alloy means also optionally NiCoCrAlY-X wherein X = Tantal (Ta) , Silicon (Si), Rhenium (Re) and/or Iron (Fe), especially consists of these elements.

The NiCoCrAlY composition preferably comprises (in wt%) :

20% - 22% Chromium (Cr) ,

10.5% - 11.5% Aluminum (Al),

0.3% - 0.5% Yttrium (Y) ,

1.5% - 2.5% Rhenium (Re) or

between 0.5% - 1.5% Rhenium and

11% - 13% Cobalt (Co) and

a remainder Nickel (Ni) .

Further preferably example for NiCoCrAlY composition compris es (in wt%) 15% - 21% Chromium (Cr) ,

24% - 26% Cobalt (Co),

9.0% - 11.5% Aluminum (Al),

0.05% - 0.7% Yttrium (Y) ,

0.5% - 2.0% Rhenium (Re) and

a remainder Nickel.

Further example of a NiCoCrAlY composition comprises (in wt% ) :

22% - 24% Cobalt (Co) ,

14% - 16% Chromium (Cr) , 10.5% - 11.5% Aluminum (Al),

0.2% - 0.4% Yttrium (Y) ,

optional 0.3% - 0.9% Tantalum (Ta) ,

remainder Nickel (Ni) .

Figure 1 shows a method how to apply the inventive material during welding and figure 2 shows a schematic arrangement to use the inventive powder for additive manufacturing, espe cially via laser.

The description and the figures are only examples of the in vention .

This method and the material can be used to build up totally new component starting on a base plate or to repair an exist ing substrate 4 which both means a build up of material.

The build up of material is necessary to erosion or cracks which have been removed. In this case, only for example, a blade tip is repaired by building up the material onto a blade tip 7. The surface 10 of the substrate 4 reveals the base on which the material is applied on. The material 16 is applied via a nozzle 13 which is connected to a powder supply 19 is an inventive material. The nozzle 13 also includes a laser which together with the powder 16 is used for welding by melting the powder via a laser beam (not shown) .

The inventive material can also be produced as a rod and or a wire and can be used via wire welding.

In figure 2 another application of the inventive material is shown .

Here a selective laser melting process (also electron beams can be used instead of a laser) wherein a powder bed 22 with the inventive powder mixture is used to create a totally new component or even to repair a substrate 4. The substrate 4 is totally inside the powder bed 22 and a laser 25 with a laser beam 28 is used to melt or to sinter partially a powder where a material build up onto the sub- strate 4 where it is needed or wanted.

The inventive material is a metallic powder mixture of three different powders.

Especially the powder mixture comprises alloy 247 or gener- ally a nickel based super alloy and a NiCoCrAlY, and also comprises optionally additions like Rhenium (Re) , Tantalum (Ta) and/or Silicon (Si), and a braze alloy which has at least a melting point at least 20K lower than the nickel based super alloy.

Further examples for the nickel base super alloy are listed in figure 3.