Additive manufacturing of metal alloys and metal alloy matrix composites

1. A method of producing an aluminum article, comprising:

providing a supply of an aluminum alloy in powder form having a D50 particle size in a range of about 5 μm to about 150 μm;

providing a supply of a nucleant material, said nucleant material lowering the nucleation energy required to crystallize said aluminum alloy;

blending said supply of aluminum alloy powder and said nucleant material to form a blended mixture;

forming said blended mixture into a first layer;

subjecting at least a portion of said first layer to energy sufficient to raise the temperature of at least a portion of said first layer to at least the liquidus temperature of said aluminum alloy;

allowing at least a portion of said first layer to cool to a temperature sufficient to allow said aluminum alloy to recrystallize;

forming a second layer of said blended mixture on said first layer; and

repeating said subjecting and allowing steps on said second layer to form an additional portion of said article.

2. The method of claim 1 , wherein said nucleant material comprises one or more selected from the group consisting of a nucleant and a nucleant precursor.

3. The method of claim 1 , wherein said nucleant material comprises one or more selected from the group consisting of Al 3 Ti, Al 3 Zr, AlB, AlB 2 , TiB, TiB 2 , ZrB, ZrB 2 , Al 3 Hf, Al 3 Sc, Al 4 C 3 , TiC, and compounds thereof.

4. The method of claim 1 , wherein said nucleant material comprises one or more selected from the group consisting of Al 4 C 3 and TiC.

5. The method of claim 1 , wherein said nucleant material crystallizes prior to significant recrystallization of said aluminum alloy.

6. The method of claim 1 , wherein said nucleant material is crystalline at a temperature greater than the liquidus temperature of said aluminum alloy.

7. The method of claim 1 , further comprising providing a supply of a binder and wherein said blending comprises blending said binder, said aluminum alloy, and said nucleant material to form said blended mixture.

8. The method of claim 1 , wherein said nucleant material comprises a nucleant precursor and wherein said subjecting provides energy sufficient to initiate a reaction with the nucleant precursor to form a nucleant, said nucleant lowering the nucleation energy required to recrystallize said aluminum alloy.

9. The method of claim 8 , wherein said nucleant precursor comprises one or more selected from the group consisting of Ti, Zr, Hf, B, Sc, and C.

10. The method of claim 9 , wherein the reaction of said nucleant precursor results in the formation of one or more nucleants selected from the group consisting of Al 3 Ti, Al 3 Zr, AlB, AlB 2 , TiB, TiB 2 , ZrB, ZrB 2 , Al 3 Hf, Al 3 Sc, Al 4 C 3 , TiC, and compounds thereof.

11. The method of claim 1 , wherein said aluminum alloy lacks silicon in an amount sufficient to depress the nucleation ability of said nucleant material.

12. The method of claim 1 , wherein said subjecting step comprises subjecting said first and second layers to directed energy.

13. The method of claim 12 , wherein said subjecting said first and second layers to directed energy comprises directing a laser beam on said first and second layers.

14. The method of claim 13 , wherein said aluminum alloy powder has a D50 particle size in a range of about 5 μm to about 80 μm.

15. The method of claim 12 , wherein said subjecting said first and second layers to directed energy comprises directing an electron beam on said first and second layers.

16. The method of claim 15 , wherein said aluminum alloy powder has a D50 particle size in a range of about 60 μm to about 150 μm.

17. The method of claim 1 , wherein said aluminum alloy comprises a wrought aluminum alloy.

18. The method of claim 1 , wherein said aluminum alloy comprises a casting aluminum alloy.

19. The method of claim 1 , wherein said aluminum alloy comprises a heat-treatable aluminum alloy.

20. The method of claim 1 , wherein said aluminum alloy comprises a work-hardenable aluminum alloy.

21. The method of claim 1 , wherein said blending further comprises blending said aluminum alloy powder and said nucleant material with a liquid to form a blended paste, said blended paste comprising a substantially homogenous mixture of said aluminum alloy powder and said nucleant material and wherein said forming the first and second layers comprises extruding the blended paste to form said first and second layers.

22. The method of claim 1 , further comprising repeating said forming, subjecting, and allowing steps until the aluminum article is fully formed.

23. The method of claim 22 , further comprising subjecting the aluminum article to a heat treatment step.

24. A method of producing an article, comprising:

providing a supply of an aluminum alloy in powder form having a D50 particle size in a range of about 5 μm to about 150 μm;

providing a supply of a nucleant precursor material;

blending said supply of aluminum alloy powder and said nucleant precursor material powder to form a blended mixture;

forming the blended mixture into a first layer;

subjecting at least a portion of the first layer to energy sufficient to initiate a reaction with said nucleant precursor material to form at least one nucleant, said at least one nucleant lowering the energy of nucleation of said aluminum alloy, said energy also being sufficient to raise the temperature of at least a portion of the first layer to at least the liquidus temperature said the aluminum alloy;

allowing at least a portion of the first layer to cool to a temperature sufficient to allow said aluminum alloy to recrystallize; and

repeating said forming, subjecting, and allowing steps on subsequent layers until the article is fully formed.

25. A method of producing a metal alloy article, comprising:

providing a supply of a metal alloy in powder form having a D50 particle size in a range of about 5 μm to about 150 μm;

providing a supply of a nucleant material, said nucleant material lowering the energy of nucleation of said metal alloy;

blending said supply of metal alloy powder and said nucleant material to form a blended mixture;

forming the blended mixture into a first layer;

subjecting at least a portion of the first layer to energy sufficient to raise the temperature of the first layer to at least the liquidus temperature of said metal alloy;

allowing at least a portion of the first layer to cool to a temperature sufficient to allow the metal alloy to recrystallize; and

repeating said forming, subjecting, and allowing steps on subsequent layers until the metal alloy article is formed.

26. The method of claim 25 , wherein said providing a supply of the metal alloy in powder form comprises providing a supply of a nickel alloy in powder form.

27. The method of claim 25 , wherein said providing a supply of the metal alloy in powder form comprises providing a supply of an Inconel alloy in powder form.

28. The method of claim 25 , wherein said providing a supply of the metal alloy in powder form comprises providing a supply of a steel alloy in powder form.

29. The method of claim 1 , wherein said nucleant material comprises one or more selected from the group consisting of yttrium, strontium, titanium, boron, and intermetallics thereof.

30. The method of claim 1 , wherein said nucleant material comprises one or more Lanthanum series elements, intermetallics, and oxides thereof.