Heat treatable aluminum alloys having magnesium and zinc and methods for producing the same
New magnesium-zinc aluminum alloy bodies and methods of producing the same are disclosed. The new magnesium-zinc aluminum alloy bodies generally include 3.0-6.0 wt. % magnesium and 2.5-5.0 wt. % zinc, where at least one of the magnesium and the zinc is the predominate alloying element of the aluminum alloy bodies other than aluminum, and wherein (wt. % Mg)/(wt. % Zn) is from 0.6 to 2.40, and may be produced by preparing the aluminum alloy body for post-solutionizing cold work, cold working by at least 25%, and then thermally treating. The new magnesium-zinc aluminum alloy bodies may realize improved strength and other properties.
1. A method comprising:
(a) preparing an aluminum alloy body for post-solutionizing cold working, the aluminum alloy body comprising 3.25-6.0 wt. % magnesium and 2.5-5.0 wt. % zinc, where at least one of the magnesium and the zinc is the predominate alloying element of the aluminum alloy body other than aluminum, and wherein a ratio of wt. % Mg, to wt. % Zn is from 0.6 to 2.40;
(i) wherein the preparing comprises solutionizing by solution heat treating and then quenching the aluminum alloy body, where the quenching reduces the temperature of the aluminum alloy body to a temperature of not greater than 200° F. and a rate of at least 200° F. per second;
(b) after the preparing step, cold working the aluminum alloy body, wherein the cold working induces at least 25% cold work in the aluminum alloy body;
(c) after the cold working step, thermally treating the aluminum alloy body, wherein the thermally treating step comprises:
(i) forming the aluminum alloy body into a predetermined shaped product, wherein, during the forming step, the aluminum alloy body is subjected to a temperature in the range of from at least 150° F. to below the recrystallization temperature of the aluminum alloy body.
2. The method of claim 1 , wherein the thermally treating step comprises:
heating the aluminum alloy body for a time and at a temperature sufficient to achieve a selected condition, wherein the heating step occurs before the forming step.
3. The method of claim 2 , wherein the selected condition is an underaged condition, and wherein the method comprises:
selecting the underaged condition, wherein the selecting step occurs prior to the thermally treating step;
completing the heating step to achieve the underaged condition.
4. The method of claim 3 , comprising
after the completing step, performing the forming step, wherein, after the forming, the predetermined shaped product achieves at least one predetermined property.
5. The method of claim 4 , wherein the at least one predetermined property is a predetermined strength.
6. The method of claim 4 , wherein the at least one predetermined property is a predetermined combination of strength and ductility.
7. The method of claim 5 , wherein the predetermined property is an underaged condition.
8. The method of claim 7 , wherein the underaged condition is within 30% of peak strength.
9. The method of claim 7 , wherein the underaged condition is within 10% of peak strength.
10. The method of claim 1 , wherein the heating step is a first heating step, wherein the thermally treating step comprises:
second heating of the aluminum alloy body, wherein the second heating occurs after the forming step.
11. The method of claim 10 , wherein the second heating comprises heating the aluminum alloy body to achieve a second selected condition.
12. The method of claim 11 , wherein the second selected condition is one of a second predetermined strength, a second predetermined ductility, and a second predetermined combination of strength and ductility.
13. The method of claim 12 , wherein the second predetermined strength is peak strength.
14. The method of claim 12 , wherein the predetermined strength is an overaged strength, wherein the overaged strength is at least 2% lower than the peak strength.
15. The method of claim 1 , wherein, after the forming step (c)(i), the predetermined shaped product realizes higher long-transverse tensile yield strength relative to the long-transverse tensile yield strength of the aluminum alloy body in an as cold worked condition.
16. The method of claim 1 , wherein, after the forming step, the predetermined shaped product is within 10% of peak strength.
17. The method of claim 1 , wherein, after the forming step, the predetermined shaped product is within 5% of peak strength.
18. The method of claim 1 , wherein the cold working comprises cold rolling the aluminum alloy body into a sheet or plate.
19. The method of claim 1 , wherein the aluminum alloy body comprises 3.5-6.0 wt. % magnesium and 2.5-5.0 wt. % zinc, where at least one of the magnesium and the zinc is the predominate alloying element of the aluminum alloy body other than aluminum, and wherein the ratio of wt. % Mg to wt. % Zn is from 0.6 to 2.40.
20. The method of claim 1 , wherein the aluminum alloy body comprises 3.75-6.0 wt. % magnesium and 2.5-5.0 wt. % zinc, where at least one of the magnesium and the zinc is the predominate alloying element of the aluminum alloy body other than aluminum, and wherein the ratio of wt. % Mg to wt. % Zn is from 0.6 to 2.40.