High strength 7XXX series aluminum alloys and methods of making the same
Described herein are 7xxx series aluminum alloys with unexpected properties and novel methods of producing such aluminum alloys. The aluminum alloys exhibit high strength and are highly formable. The alloys are produced by continuous casting and can be hot rolled to a final gauge and/or a final temper. The alloys can be used in automotive, transportation, industrial, and electronics applications, just to name a few.
1. A method of producing an aluminum alloy product, comprising:
continuously casting an aluminum alloy to form a slab, wherein the aluminum alloy comprises 0.03-1.2 wt. % Si, 0.0-1.5 wt. % Fe, 1.0-3.0 wt. % Cu, 0.005-0.9 wt. % Mn, 0.7-8.7 wt. % Mg, 0-0.3 wt. % Cr, 1.7-18.3 wt. % Zn, 0.005-0.6 wt. % Ti, 0-0.4 wt. % Zr, up to 0.15 wt. % of impurities, and Al;
cooling the slab at a rate from 1° C./s to 200° C./s upon exit from a continuous caster that continuously casts the slab;
heating the slab to a temperature of no more than 500° C. at a heating rate of from 100° C./min to 10° C./min;
soaking the heated slab at the temperature for a soak time of 10 seconds to 36 hours; and
hot rolling the slab to a final gauge without cold rolling the slab prior to the final gauge,
wherein the aluminum alloy product has a yield strength of 400 to 650 MPa at peak age condition.
2. The method of claim 1 , wherein the aluminum alloy comprises 0.06-0.35 wt. % Si, 0.12-0.45 wt. % Fe, 1.0-3.0 wt. % Cu, 0.01-0.25 wt. % Mn, 1.5-5.0 wt. % Mg, 0.01-0.25 wt. % Cr, 3.5-15.5 wt. % Zn, 0.01-0.15 wt. % Ti, 0.001-0.18 wt. % Zr, and up to 0.15 wt. % of impurities, and Al.
3. The method of claim 1 , wherein the aluminum alloy comprises 0.07-0.13 wt. % Si, 0.16-0.22 wt. % Fe, 1.3-2.0 wt. % Cu, 0.01-0.08 wt. % Mn, 2.3-2.65 wt. % Mg, 0.02-0.2 wt. % Cr, 5.0-10.0 wt. % Zn, 0.015-0.04 wt. % Ti, 0.001-0.15 wt. % Zr, up to 0.15 wt. % of impurities, and Al.
4. The method of claim 1 , wherein the cooling step comprises quenching the slab with water.
5. The method of claim 1 , wherein the cooling step comprises air cooling the slab.
6. The method of claim 1 , wherein the continuously cast slab is coiled before the step of hot rolling the slab.
7. The method of claim 1 , further comprising:
coiling the slab into an intermediate coil before hot rolling the slab to the final gauge;
pre-heating the intermediate coil before hot rolling the slab to the final gauge; and
homogenizing the intermediate coil before hot rolling the slab to the final gauge.
8. The method of claim 1 , further comprising:
solutionizing the aluminum alloy product of the final gauge;
quenching the aluminum alloy product of the final gauge; and
aging the aluminum alloy product of the final gauge.
9. The method of claim 1 , wherein the slab is devoid of cracks having a length greater than 8.0 mm after the continuous casting and before the hot rolling.
10. The method of claim 1 , further comprising pre-heating the slab prior to hot rolling.
11. A method of producing an aluminum alloy, comprising:
continuously casting an aluminum alloy to form a slab, wherein the aluminum alloy comprises 0.03-1.2 wt. % Si, 0.06-1.5 wt. % Fe, 1.0-3.0 wt. % Cu, 0.005-0.9 wt. % Mn, 0.7-8.7 wt. % Mg, 0-0.3 wt. % Cr, 1.7-8.3 wt. % Zn, 0.005-0.6 wt. % Ti, 0-0.4 wt. % Zr, up to 0.15 wt. % of impurities at up to 0.05 wt. % for each impurity, and
Al;
cooling the slab at a rate from 1° C./s to 200° C./s upon exit from a continuous caster that continuously casts the slab;
heating the slab to a temperature of no more than 500° C. at a heating rate of from 100° C./min to 10° C./min; and
hot rolling the slab to a final gauge and a final temper; wherein the aluminum alloy product has a yield strength of 400 to 6501VIPa at peak age condition.
12. The method of claim 11 , wherein the aluminum alloy comprises 0.07-0.13 wt. % Si, 0.16-0.22 wt. % Fe, 1.3-2.0 wt. % Cu, 0.01-0.08 wt. % Mn, 2.3-2.65 wt. % Mg, 0.02-0.2 wt. % Cr, 5.0-10.0 wt. % Zn, 0.015-0.04 wt. % Ti, 0.001-0.15 wt. % Zr, up to 0.15 wt. % of impurities, and Al.
13. The method of claim 11 , wherein the slab is devoid of cracks having a length greater than 8.0 mm after the continuous casting and before the hot rolling.
14. The method of claim 11 , wherein a cold rolling step is not performed.