7XXX aluminum alloys, and methods for producing the same
View Patent ↗New 7xxx aluminum alloy bodies and methods of producing the same are disclosed. The new 7xxx aluminum alloy bodies 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 7xxx aluminum alloy bodies may realize improved strength and other properties.
1. A method comprising:
(a) preparing an aluminum alloy body for post-solutionizing cold work, wherein the aluminum alloy body includes an aluminum alloy having 2.0-22 wt. % zinc, at least 1.0 wt. % Cu, and less than 0.25 wt. % Mn, wherein the zinc is the predominate alloying element of the aluminum alloy other than aluminum;
(i) wherein the preparing step comprises solutionizing of the aluminum alloy body;
(b) after the preparing step (a), cold working the aluminum alloy body by more than 50%; and
(c) after the cold working step (b), thermally treating the aluminum alloy body; and
(d) contemporaneous to the thermally treating step (c), forming the aluminum alloy body into a final shaped aluminum alloy product;
wherein the cold working and the thermally treating steps are accomplished to achieve an increase in long-transverse tensile yield strength as compared to a reference-version of the aluminum alloy body in the as cold-worked condition, and
wherein the cold working and the thermally treating steps are accomplished such that the aluminum alloy body achieves at least a 6% increase in tensile yield strength relative to a reference-version of the aluminum alloy body in the T6 condition.
2. The method of claim 1 , wherein the solutionizing step (a)( 1 ) comprises quenching the aluminum alloy body, and Wherein the quenching occurs in the absence of deformation of the aluminum alloy body.
3. The method of claim 2 , wherein no purposeful thermal heating treatments are applied to the aluminum alloy body between the solutionizing step (a)(i), and the cold working step (b).
4. The method of claim 3 , wherein the cold working step (b) occurs in the absence of purposeful heating of the aluminum alloy body.
5. The method of claim 4 , wherein the cold working step (b) comprises reducing the aluminum alloy body to its substantially final form.
6. The method of claim 5 , wherein the cold working step (b) comprises cold rolling the aluminum alloy body to final gauge.
7. The method of claim 1 , wherein the cold working step (b) comprises cold working the aluminum alloy body in the range of from at least 55% to 90%.
8. The method of claim 1 , wherein the thermally treating step (c) comprises maintaining the aluminum alloy body below its recrystallization temperature.
9. The method of claim 8 , wherein the cold working step (b) and the thermally treating step (c) are performed such that the aluminum alloy body realizes a predominately unrecrystallized microstructure.
10. The method of claim 1 , wherein the cold working step (b) comprises:
first cold working a first portion of the aluminum alloy body by a first cold working amount; and
second cold working a second portion of the aluminum alloy body by a second cold working amount, wherein the second cold working amount is different than the first cold working amount.
11. The method of claim 1 , wherein the preparing step (a) comprises:
producing a multi-layered aluminum alloy product;
(i) wherein a first layer of the multi-layered aluminum alloy product comprises the 2.0-22 wt, % zinc, the at least 1.0 wt. % Cu, and the less than 0.25 wt. % Mn; and
(ii) wherein another layer of the multi-layered aluminum alloy product comprises a composition different than the first layer of the multi-layered aluminum alloy product;
homogenizing the multi-layered aluminum alloy product; and
hot rolling the multi-layered aluminum alloy product into the aluminum alloy body, and then completing the solutionizing step (a)(i).