Methods of making highly-formable aluminum alloys and aluminum alloy products thereof
Provided herein are highly-formable aluminum alloys and methods of making such alloys. The method of preparing aluminum alloys described herein can include a low final cold reduction step and/or an optional inter-annealing step to produce randomly distributed crystallographic texture components that produce an isotropic aluminum alloy product exhibiting improved formability and deep drawability. The methods described herein result in aluminum alloy microstructures having a balance of alpha fibers and beta fibers that promote improved formability of aluminum alloy sheets. The resulting improvements in quality allow for shaping processes with reduced rates of spoilage.
1. A method of producing an aluminum alloy product, comprising:
casting an aluminum alloy to produce a cast aluminum alloy article, wherein the aluminum alloy comprises 0.5 to 2.0 wt. % Si, 0.1 to 0.4 wt. % Fe, up to 0.4 wt. % Cu, up to 0.5 wt. % Mg, 0.02 to 0.1 wt. % Mn, up to 0.02 wt. % Cr, up to 0.15 wt. % Ti, up to 0.1 wt. % Zn, up to 0.15 wt. % impurities, and Al;
homogenizing the cast aluminum alloy article to produce a homogenized cast aluminum alloy article;
hot rolling the homogenized cast aluminum article to produce a hot rolled product, wherein the exit temperature of the hot rolled product ranges from 200° C. to 290° C.;
cold rolling the hot rolled product in a first cold rolling step to produce a first cold rolled product having an intermediate gauge, wherein the first cold rolling step results in a thickness reduction from 25% to 70% from the hot rolled product to the first cold rolled product;
inter-annealing the first cold rolled product at an inter-annealing temperature from 300° C. to 450° C.; and
cold rolling the first cold rolled product in a second cold rolling step to produce a final gauge aluminum alloy product having a final gauge, wherein the second cold rolling step results in a thickness reduction from 40% to 70% from the intermediate gauge to the final gauge aluminum alloy product;
wherein the final gauge aluminum alloy product comprises a volume fraction of alpha fibers of at least 8%, a volume fraction of beta fibers of at least 6%, and a ratio of the volume fraction of the alpha fibers to the volume fraction of the beta fibers ranging from 0.5:1 to 2:1.
2. The method of claim 1 , wherein the intermediate gauge comprises a thickness ranging from 2 mm to 6 mm.
3. The method of claim 1 , further comprising solution heat treating the final gauge aluminum alloy product.
4. The method of claim 1 , wherein the final gauge comprises a thickness ranging from 0.1 mm to 3 mm.
5. The method of claim 1 , wherein the casting step comprises direct chill casting or continuous casting.
6. The method of claim 1 , wherein the homogenizing step is performed at a homogenization temperature of from 450° C. to 600° C.
7. The method of claim 1 , wherein the hot rolling step is performed at a hot rolling temperature of from 500° C. to 560° C.
8. The method of claim 1 , wherein the final gauge aluminum alloy product exhibits a yield strength of at least 5% greater than a yield strength of a 6xxx series aluminum alloy prepared by a method including a final cold rolling step that results in a greater than 70% reduction in thickness from the intermediate gauge aluminum alloy to the final gauge aluminum alloy.
9. The method of claim 1 , wherein the final gauge aluminum alloy product exhibits an ultimate tensile strength of at least 3% greater than an ultimate tensile strength of a 6xxx series aluminum alloy prepared by a method including a final cold rolling step that results in a greater than 70% reduction in thickness from the intermediate gauge aluminum alloy to the final gauge aluminum alloy.
10. The method of claim 1 , wherein the final gauge aluminum alloy product has a total elongation of at least 5% greater than a total elongation of a 6xxx series aluminum alloy prepared by a method including a final cold rolling step that results in a greater than 70% reduction in thickness from the intermediate gauge aluminum alloy to the final gauge aluminum alloy.