Dispersion strengthened L12 aluminum alloys

• US 20090263277A1
• Filed: 04/18/2008
• Published: 10/22/2009
• Est. Priority Date: 04/18/2008
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Pandey, Awadh B.
• Granted Patent: US 8,017,072 B2
• Time in Patent Office: Days
• US Class Current: 420/543
• CPC Class Codes: C22C 21/00 Alloys based on aluminium
• CPC Class Codes: C22C 21/06 with magnesium as the next major constituent
• CPC Class Codes: C22F 1/04 of aluminium or alloys based thereon
• CPC Class Codes: C22F 1/047 of alloys with magnesium as the next major constituent

Abstract

An improved L1₂ aluminum alloy having magnesium or nickel; at least one of scandium, erbium, thulium, ytterbium, and lutetium; at least one of gadolinium, yttrium, zirconium, titanium, hafnium, and niobium; and at least one ceramic reinforcement. Aluminum oxide, silicon carbide, aluminum nitride, titanium boride, titanium diboride and titanium carbide are suitable ceramic reinforcement particles. These alloys derive strengthening from mechanisms based on dislocation-particle interaction and load transfer to stiffen reinforcements.

Claims

1. An aluminum alloy having high strength, ductility and toughness, comprising:

at least one metal selected from the group comprising;

about 1 to about 8 weight percent magnesium and about 1 to about 10 weight percent nickel;

at least one first element selected from the group comprising;

about 0.1 to about 0.5 weight percent scandium, about 0.1 to about 6 weight percent erbium, about 0.1 to about 10 weight percent thulium, about 0.1 to about 15 weight percent ytterbium, and about 0.1 to about 12 weight percent lutetium;

at least one second element selected from the group comprising;

about 0.1 to about 4 weight percent gadolinium, about 0.1 to about 4 weight percent yttrium, about 0.05 to about 1 weight percent zirconium, about 0.05 to about 2 weight percent titanium, about 0.05 to about 2 weight percent hafnium, and about 0.05 to 1 weight percent niobium;

at least one ceramic selected from the group comprising;

about 5 to about 40 volume percent aluminum oxide, about 5 to about 40 volume percent silicon carbide, about 5 to about 40 volume percent aluminum nitride, about 5 to 40 volume percent titanium diboride, about 5 to about 40 volume percent titanium boride, and about 5 to about 40 volume percent titanium carbide; and

the balance substantially aluminum.

2. The alloy of claim 1 further comprising at least one element selected from:

about 3 to about 12 weight percent zinc;

about 0.2 to about 3 weight percent copper;

about 0.5 to about 3 weight percent lithium; and

about 4 to about 25 weight percent silicon.

3. The alloy of claim 1, wherein the alloy comprises an aluminum solid solution matrix containing a plurality of dispersed Al₃X second phases having L1₂ structures, wherein X includes at least one first element and at least one second element.

4. The alloy of claim 1, comprising no more than about 1 weight percent total impurities.

5. The alloy of claim 1, comprising no more than about 0.1 weight percent iron, about 0.1 weight percent chromium, about 0.1 weight percent manganese, about 0.1 weight percent vanadium, about 0.1 weight percent cobalt, and about 0.1 weight percent nickel.

6. The alloy of claim 1, which is formed by admixing the ceramic particle reinforcements into a powder comprising the metal, first element, second element and aluminum, and thereafter consolidating the admixture into the alloy.

7. The alloy of claim 1, which is formed by admixing the ceramic particle reinforcements into the molten metal, first element, second element and aluminum using casting process and thereafter pouring the material into a mold to produce the alloy.

8. The alloy of claim 1 further comprising at least one of:

about 0.001 to about 0.1 weight percent sodium, about 0.001 to about 0.1 weight percent calcium, about 0.001 to about 0.1 weight percent strontium, about 0.001 to about 0.1 weight percent antimony, about 0.001 to about 0.1 weight percent barium, and about 0.001 to about 0.1 weight percent phosphorus.

9. The alloy of claim 1, wherein the alloy is formed by a process comprising at least one of:

cryomilling, conventional ball milling, equi-channel extrusion, spray deposition, cold spray and plasma spray.

10. The aluminum alloy of claim 1, wherein the alloy is capable of being used at temperatures from about −

420°

F. (−

251°

C.) up to about 650°

F. (343°

C.).

11. A heat treatable aluminum alloy comprising:

at least one metal selected from about 1 to about 8 weight percent magnesium and about 1 to about 10 weight percent nickel;

an aluminum solid solution matrix containing a plurality of dispersed Al₃X second phases having L1₂ structures where X comprises at least one of scandium, erbium, thulium, ytterbium, lutetium, and at least one of gadolinium, yttrium, zirconium, titanium, hafnium, niobium; and

at least one ceramic selected from the group comprising;

about 5 to about 40 volume percent aluminum oxide, about 5 to about 40 volume percent silicon carbide, about 5 to about 40 volume percent aluminum nitride, about 5 to about 40 volume percent titanium diboride, about 5 to about 40 volume percent titanium boride, and about 5 to about 40 volume percent titanium carbide; and

the balance substantially aluminum.

12. The alloy of claim 11, wherein the alloy comprises at least one of:

about 0.1 to about 0.5 weight percent scandium, about 0.1 to about 6 weight percent erbium, about 0.1 to about 10 weight percent thulium, about 0.1 to about 15 weight percent ytterbium, about 0.1 to about 12 weight percent lutetium, about 0.1 to about 4 weight percent gadolinium, about 0.1 to about 4 weight percent yttrium, about 0.05 to about 1 weight percent zirconium, about 0.05 to about 2 weight percent titanium, about 0.05 to about 2 weight percent hafnium, about 0.05 to about 1 weight percent niobium, about 5 to about 40 volume percent aluminum oxide, about 5 to about 40 volume percent silicon carbide, about 5 to about 40 volume percent aluminum nitride, about 5 to about 40 volume percent titanium diboride, about 5 to about 40 volume percent titanium boride, and about 5 to about 40 volume percent titanium carbide.

13. The alloy of claim 11 further comprising at least one element selected from:

about 3 to about 12 weight percent zinc;

about 0.2 to about 3 weight percent copper;

about 0.5 to about 3 weight percent lithium; and

about 4 to about 25 weight percent silicon.

14. A method of forming an aluminum alloy having high strength, ductility and toughness, the method comprising:

(a) forming an alloy powder comprising;

at least one metal selected from the group comprising;

about 1 to about 8 weight percent of magnesium and about 1 to about 10 weight percent of nickel;

at least one first element selected from the group comprising;

about 0.1 to about 0.5 weight percent scandium, about 0.1 to about 6 weight percent erbium, about 0.1 to about 10 weight percent thulium, about 0.1 to about 15 weight percent ytterbium, and about 0.1 to about 12 weight percent lutetium;

at least one second element selected from the group comprising;

about 0.1 to about 4 weight percent gadolinium, about 0.1 to about 4 weight percent yttrium, about 0.05 to about 1 weight percent zirconium, about 0.05 to about 2 weight percent titanium, about 0.05 to about 2 weight percent hafnium, and about 0.05 to about 1 weight percent niobium; and

the balance substantially aluminum;

(b) adding at least one ceramic selected from the group comprising;

about 5 to about 40 volume percent aluminum oxide, about 5 to about 40 volume percent silicon carbide, about 5 to about 40 volume percent aluminum nitride, about 5 to about 40 volume percent titanium diboride, about 5 to about 40 volume percent titanium boride, and about 5 to about 40 volume percent titanium carbide; and

(c) consolidating the powder and ceramic to form the alloy.

15. The alloy of claim 14 further comprising at least one element selected from:

about 3 to about 12 weight percent zinc;

about 0.2 to about 3 weight percent copper;

about 0.5 to about 3 weight percent lithium; and

about 4 to about 25 weight percent silicon.

16. The method of claim 14, wherein the alloy powder is consolidated after addition of the ceramic particles to form a solid body.

17. The method of claim 16, wherein the consolidated billet is deformed by extrusion, forging or rolling before heat treating.

18. The method of claim 14, wherein the alloy is formed by melting the alloying elements together, mixing with ceramic reinforcements, solidifying the melt to form a solid body, and heat treating the solid body.

19. The method of claim 18, wherein the cast alloy is deformed by extrusion, forging or rolling before heat treating.

20. The method of claim 18, wherein solidifying comprises a casting process.

21. The method of claim 18, wherein solidifying comprises a rapid solidification process in which the cooling rate is greater than about 10³°

C./second comprising at least one of;

powder processing, atomization, melt spinning, splat quenching, spray deposition, cold spray, plasma spray, laser melting, laser deposition, ball milling, and cryomilling.

22. The method of claim 18, wherein the heat treating comprises:

solution heat treatment at about 800°

F. (426°

C.) to about 1100°

F. (593°

C.) for about thirty minutes to four hours;

quenching; and

aging at about 200°

F. (93°

C.) to about 600°

F. (315°

C.) for about two to forty-eight hours.