Aluminum-copper-lithium alloys

Patent metadata

Field	Value
Publication number	US-9587294-B2
Application number	US-201213368586-A
Country	US
Kind code	B2
Filing date	Feb 8, 2012
Priority date	Dec 4, 2007
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

Improved aluminum-copper-lithium alloys are disclosed. The alloys may include 3.4-4.2 wt. % Cu, 0.9-1.4 wt. % Li, 0.3-0.7 wt. % Ag, 0.1-0.6 wt. % Mg, 0.2-0.8 wt. % Zn, 0.1-0.6 wt. % Mn, and 0.01-0.6 wt. % of at least one grain structure control element, the balance being aluminum and incidental elements and impurities. The alloys achieve an improved combination of properties over prior art alloys.

First claim

What is claimed is:

1. A method comprising:
(a) casting an aluminum alloy ingot comprising:
3.6 - 4.0 wt. % Cu;
1.1 - 1.2 wt. % Li;
0.4 - 0.55 wt. % Ag;
0.25 - 0.45 wt. % Mg;
0.4 - 0.6 wt. % Zn;
0.2 - 0.4 wt. % Mn; and
0.05 - 0.15 wt. % Zr;
the balance being aluminum and incidental elements and impurities;

(b) homogenizing the aluminum alloy ingot, wherein the homogenizing step (b) comprises:
first heating the aluminum alloy ingot to a first temperature and for a first period of time, wherein the first temperature is from 900° F. to 940° F., and wherein the first period of time is at least 2 hours;
second heating the aluminum alloy ingot to a second temperature and for a second period of time, wherein the second temperature is higher than the first temperature, and wherein the second period of time is at least two hours;

(c) extruding the aluminum alloy ingot into an extruded product;
(d) solution heat treating and quenching the extruded product;
(e) mechanically stress relieving the extruded product by cold working the extruded product 1-4%, wherein the total amount of cold work does not exceed 4%; and
(f) artificially aging the extruded product.

2. The method of claim 1 , wherein the alloy contains at least 3.7 wt. % Cu.

3. The method of claim 1 , wherein the alloy contains at least 3.8 wt. % Cu.

4. The method of any of claims 1 - 3 , wherein the alloy contains not greater than 3.95 wt. % Cu.

5. The method of claim 1 , wherein the alloy contains at least 0.45wt. % Zn.

6. The method of claim 1 , wherein the alloy contains not greater than 0.55 wt, % Zn.

7. The method of claim 1 , wherein the alloy contains at least 0.45wt. % Ag.

8. The method of claim 1 , wherein the second heating occurs at a temperature of from 940° F. to 955° F.

9. The method of claim 1 , wherein the first period of time is at least 7 hours.

10. The method of claim 1 , wherein the solution heat treating and quenching step (d) comprises solution heat treating the extruded product at a temperature of from 940° F. to 955° F.

11. The method of claim 1 , wherein total amount of the cold work of step (e) does not exceed 3.0%.

12. The method of claim 1 , wherein the total amount of the cold work of step (e) does not exceed 2.5%.

13. The method of claim 1 , wherein the artificially aging step (f) comprises:
first aging the extruded product at a first artificial aging temperature for a first period of artificial aging time;
second aging the extruded product at a second artificial aging temperature for a second period of artificial aging time, wherein the second artificial aging temperature is different than the first artificial aging temperature.

14. The method of claim 13 , wherein the second artificial aging temperature is higher than the first artificial aging temperature.

15. The method of claim 14 , wherein the first artificial aging temperature is from 200° F. to 275° F.

16. The method of claim 15 , wherein the second artificial aging temperature is from 290° F. to 325° F.

17. The method of any of claims 15 - 16 , wherein the first period of artificial aging time is at least 12 hours.

18. The method of claim 17 , wherein the second period of artificial aging time is at least 16 hours.

19. The method of any of claims 1 , 11 , and 12 , wherein the extruded product realizes a tensile yield strength of at least 84 ksi.

20. The method of any of claims 1 , 11 , and 12 , wherein the extruded product realizes a tensile yield strength of at least 86 ksi.

21. The method of any of claims 1 , 11 and 12 , wherein the extruded product realizes a tensile yield strength of at least 88 ksi.

22. The method of any of claims 1 , 11 and 12 , wherein the extruded product realizes a tensile yield strength of at least 90 ksi.

23. The method of any of claims 1 , 11 and 12 , wherein the extruded product realizes a tensile yield strength of at least 97 ksi.

24. The method of claim 18 , wherein the first period of time is from 12 to 17 hours, and wherein the second period of time is from 16 to 22 hours.

Assignees

• Colvin Edward L
• Rioja Roberto J
• Yocum Les A
• Denzer Diana K
• Cogswell Todd K
• Bray Gary H
• Sawtell Ralph R
• Wilson Andre L
• Arconic Inc

Inventors

• Colvin Edward L
• Rioja Roberto J
• Yocum Les A
• Denzer Diana K
• Cogswell Todd K
• Bray Gary H
• Sawtell Ralph R
• Wilson Andre L

Classifications

• C22C21/16 Primary

  with magnesium · CPC title

• C22C21/12

  with copper as the next major constituent · CPC title

• C22C21/18 Primary

  with zinc · CPC title

• C22F1/057

  of alloys with copper as the next major constituent · CPC title