7xxx series aluminum alloy products in a stabilized t4 temper and methods of making the same

Abstract

The present disclosure generally provides 7xxx series aluminum alloy products in a stable T4 temper. The disclosure also provides methods of making such products, for example, using processes that include a combination of casting, rolling, solutionizing, quenching, reheating, and slow cooling. The disclosure also provides various end uses of such products, such as in automotive, transportation, electronics, and industrial applications.

What is claimed is: 
     
         1 . A method of making a rolled aluminum alloy product, comprising:
 providing a 7xxx series aluminum alloy, wherein the 7xxx series aluminum alloy is provided as a molten 7xxx series aluminum alloy;   casting the molten 7xxx series aluminum alloy to provide an aluminum alloy cast product;   homogenizing the aluminum alloy cast product to provide a homogenized aluminum alloy cast product;   rolling the homogenized aluminum alloy cast product to form a rolled aluminum alloy product; and   solutionizing and pre-aging the rolled aluminum alloy product.   
     
     
         2 . The method of  claim 1 , wherein the 7xxx series aluminum alloy is selected from the group consisting of AA7011, AA7019, AA7020, AA7021, AA7039, AA7072, AA7075, AA7085, AA7108, AA7108A, AA7015, AA7017, AA7018, AA7019A, AA7024, AA7025, AA7028, AA7030, AA7031, AA7033, AA7035, AA7035A, AA7046, AA7046A, AA7003, AA7004, AA7005, AA7009, AA7010, AA7011, AA7012, AA7014, AA7016, AA7116, AA7122, AA7023, AA7026, AA7029, AA7129, AA7229, AA7032, AA7033, AA7034, AA7036, AA7136, AA7037, AA7040, AA7140, AA7041, AA7049, AA7049A, AA7149, AA7204, AA7249, AA7349, AA7449, AA7050, AA7050A, AA7150, AA7250, AA7055, AA7155, AA7255, AA7056, AA7060, AA7064, AA7065, AA7068, AA7168, AA7175, AA7475, AA7076, AA7178, AA7278, AA7278A, AA7081, AA7181, AA7185, AA7090, AA7093, AA7095, and AA7099. 
     
     
         3 . The method of  claim 1 , wherein the 7xxx series aluminum alloy comprises:
 from 4.0 to 15.0 wt. % Zn;   from 0.1 to 3.5 wt % Cu;   from 1.0 to 4.0 wt. % Mg;   from 0.05 to 0.50 wt. % Fe;   from 0.05 to 0.30 wt. % Si;   up to 0.50 wt. % Zr;   up to 0.25 wt. % Mn;   up to 0.20 wt. % Cr;   up to 0.15 wt. % Ti;   up to 0.15 wt. % impurities; and   Al.   
     
     
         4 . The method of  claim 3 , wherein the 7xxx series aluminum alloy comprises:
 from 5.6 to 9.3 wt. % Zn;   from 0.2 to 2.6 wt. % Cu;   from 1.4 to 2.8 wt. % Mg;   from 0.10 to 0.35 wt. % Fe;   from 0.05 to 0.20 wt. % Si;   up to 0.25 wt. % Zr;   up to 0.05 wt. % Mn;   up to 0.05 wt. % Cr;   up to 0.05 wt. % Ti;   up to 0.15 wt. % impurities; and   Al.   
     
     
         5 . The method of  claim 3 , further comprising up to 0.10 wt. % of one or more elements selected from the group consisting of Mo, Nb, Be, B, Co, Sn, Sr, V, In, Hf, Ag, Sc, Ni, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. 
     
     
         6 . The method of  claim 1 , wherein the rolled aluminum alloy product is an aluminum alloy sheet or an aluminum alloy shate. 
     
     
         7 . The method of  claim 6 , wherein the rolled aluminum alloy product has a thickness of no more than 15 mm. 
     
     
         8 . The method of  claim 1 , wherein the casting comprises direct chill (DC) casting or continuous casting. 
     
     
         9 . The method of  claim 1 , wherein the rolling comprises hot rolling, cold rolling, or any combination thereof. 
     
     
         10 . The method of  claim 1 , further comprising quenching the rolled aluminum alloy product after the solutionizing and preceding the pre-aging. 
     
     
         11 . The method of  claim 1 , wherein the pre-aging comprises heating the rolled aluminum alloy product to a pre-aging temperature ranging from 60° C. to 130° C. 
     
     
         12 . The method of  claim 1 , wherein the pre-aging is conducted for a period of time up to about 24 hours. 
     
     
         13 . The method of  claim 1 , further comprising, after the pre-aging, cooling the rolled aluminum alloy product to room temperature over a period of time ranging from 12 hours to 48 hours. 
     
     
         14 . The method of  claim 1 , further comprising, after the pre-aging, coiling the rolled aluminum alloy product, and, then, cooling the rolled aluminum alloy product to room temperature. 
     
     
         15 . The method of  claim 14 , wherein the coiling is carried out at a temperature of no more than 5° C. below the pre-aging temperature. 
     
     
         16 . The method of  claim 15 , wherein the cooling is carried out over a period of time ranging from 12 hours to 48 hours. 
     
     
         17 . The method of  claim 1 , further comprising coiling the rolled aluminum alloy product after the pre-aging. 
     
     
         18 . The method of  claim 1 , wherein the rolled aluminum alloy product has a yield strength (R p ) of at least 240 MPa immediately following pre-aging, wherein the yield strength (R p ) is measured according to ISO 6892-1. 
     
     
         19 . The method of  claim 1 , wherein the rolled aluminum alloy product exhibits an increase in its yield strength (R p ) of no more than 25 MPa during a post-production period immediately following the pre-aging, wherein the post-production period ranges from 7 days to 180 days. 
     
     
         20 . An aluminum alloy product, wherein the aluminum alloy product is a rolled aluminum alloy product made by a method of  claim 1 .