Al-zn-mg-cu aluminum alloy extrusions and methods of manufacture thereof

Abstract

Improved aluminum-zinc-magnesium-copper alloys and methods of making extruded products therefrom are disclosed. The alloys may be provided as wrought Al—Zn—Mg—Cu extrusions having improved combinations of strength, fracture toughness, fatigue resistance and corrosion resistance.

What is claimed is: 
     
         1 . An extruded aluminum alloy product comprising from 5.90 to 6.50 weight percent Zn, from 1.50 to 1.90 weight percent Mg, from 1.60 to 2.30 weight percent Cu, from 0.08 to 0.12 weight percent Zr, from 0.01 to 0.05 weight percent Ti, and the balance Al and incidental impurities. 
     
     
         2 . The extruded aluminum alloy product of  claim 1 , wherein the Cu is less than 2.00 weight percent. 
     
     
         3 . The extruded aluminum alloy product of  claim 1 , wherein the Cu is less than 1.90 weight percent. 
     
     
         4 . The extruded aluminum alloy product of  claim 1 , wherein the Cu is greater than 1.70 weight percent. 
     
     
         5 . The extruded aluminum alloy product of  claim 1 , wherein the Cu is greater than 1.80 weight percent. 
     
     
         6 . The extruded aluminum alloy product of  claim 1 , wherein the Cu is from 1.70 to 2.00 weight percent. 
     
     
         7 . The extruded aluminum alloy product of  claim 1 , wherein the Cu is from 1.80 to 1.90 weight percent. 
     
     
         8 . The extruded aluminum alloy product of  claim 1 , wherein the Mg is less than 1.90 weight percent. 
     
     
         9 . The extruded aluminum alloy product of  claim 1 , wherein the Mg is less than 1.80 weight percent. 
     
     
         10 . The extruded aluminum alloy product of  claim 1 , wherein the Mg is greater than 1.55 weight percent. 
     
     
         11 . The extruded aluminum alloy product of  claim 1 , wherein the Mg is greater than 1.60 weight percent. 
     
     
         12 . The extruded aluminum alloy product of  claim 1 , wherein the Mg is from 1.55 to 1.90 weight percent. 
     
     
         13 . The extruded aluminum alloy product of  claim 1 , wherein the Mg is from 1.60 to 1.80 weight percent. 
     
     
         14 . The extruded aluminum alloy product of  claim 1 , wherein the Zn is less than 6.30 weight percent. 
     
     
         15 . The extruded aluminum alloy product of  claim 1 , wherein the Zn is greater than 6.00 weight percent. 
     
     
         16 . The extruded aluminum alloy product of  claim 1 , wherein the Zn is from 6.00 to 6.30 weight percent. 
     
     
         17 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product comprises less than 0.05 weight percent Mn. 
     
     
         18 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product is substantially free of Mn. 
     
     
         19 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product further comprises from 0.01 to 0.10 weight percent Sr. 
     
     
         20 . The extruded aluminum alloy product of  claim 1 , wherein the alloy has a Zn:Mg weight ratio of less than 3.85. 
     
     
         21 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has a (Zn+Cu):Mg weight ratio of from 4.7 to 4.9. 
     
     
         22 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has a density of 0.103 lbs/in 3  or less. 
     
     
         23 . The extruded aluminum alloy product of  claim 1 , wherein the extruded aluminum alloy has a resistance to EAC when tested at 72 percent of ST TYS of greater than 100 days. 
     
     
         24 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has an L elongation of greater than 14.0 percent. 
     
     
         25 . The extruded aluminum alloy product of  claim 24 , wherein the alloy product has L TYS of greater than 70 ksi. 
     
     
         26 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has an L elongation of greater than 15.0 percent. 
     
     
         27 . The extruded aluminum alloy product of  claim 24 , wherein the alloy product has a T-L Kq of greater than 25.0 ksi √inch. 
     
     
         28 . The extruded aluminum alloy product of  claim 24 , wherein the alloy product has a T-L Kq of greater than 25.5 ksi √inch. 
     
     
         29 . The extruded aluminum alloy product of  claim 24 , wherein the alloy product has a T-L Kq of greater than 26.0 ksi V inch. 
     
     
         30 . The extruded aluminum alloy product of  claim 27 , wherein the alloy product has a L-T Kq of greater than 43.0 ksi √inch. 
     
     
         31 . The extruded aluminum alloy product of  claim 27 , wherein the alloy product has a L-T Kq of greater than 44.0 ksi √inch. 
     
     
         32 . The extruded aluminum alloy product of  claim 27 , wherein the alloy product has a L-T Kq of greater than 45.0 ksi √inch. 
     
     
         33 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has a T-L Kq of greater than 30.0 ksi √inch. 
     
     
         34 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has a T-L Kq of greater than 34.0 ksi √inch. 
     
     
         35 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has a T-L Kq of greater than 40.0 ksi √inch. 
     
     
         36 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has a T-L Kq of greater than 45.0 ksi √inch. 
     
     
         37 . The extruded aluminum alloy product of  claim 33 , wherein the alloy product has a L-T Kq of greater than 38.0 ksi √inch. 
     
     
         38 . The extruded aluminum alloy product of  claim 33 , wherein the alloy product has a L-T Kq of greater than 40.0 ksi √inch. 
     
     
         39 . The extruded aluminum alloy product of  claim 33 , wherein the alloy product has a L-T Kq of greater than 50.0 ksi √inch. 
     
     
         40 . The extruded aluminum alloy product of  claim 33 , wherein the alloy product has a L-T Kq of greater than 55.0 ksi √inch. 
     
     
         41 . The extruded aluminum alloy product of  claim 33 , wherein the alloy product has a L-T Kq of greater than 80.0 ksi √inch. 
     
     
         42 . The extruded aluminum alloy product of  claim 33 , wherein the alloy product has a L-T Kq of greater than 90.0 ksi √inch. 
     
     
         43 . The extruded aluminum alloy product of  claim 33 , wherein the alloy product has a L-T Kq of greater than 95.0 ksi √inch. 
     
     
         44 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has an ST TYS of greater than 62 ksi. 
     
     
         45 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has an ST TYS of greater than 65 ksi. 
     
     
         46 . The extruded aluminum alloy product of  claim 44 , wherein the alloy product has an S-L Klc of greater than 26 ksi √inch. 
     
     
         47 . The extruded aluminum alloy product of  claim 44 , wherein the alloy product has an S-L Klc of greater than 27 ksi √inch. 
     
     
         48 . The extruded aluminum alloy product of  claim 44 , wherein the alloy product has an S-L Klc of greater than 30 ksi √inch. 
     
     
         49 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has an S-L Klc of greater than 26 ksi √inch. 
     
     
         50 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has a L-T Klc of greater than 44 ksi √inch or a L TYS of greater than 68 ksi. 
     
     
         51 . The extruded aluminum alloy product of  claim 50 , wherein the alloy product has a L TYS of greater than 70 ksi. 
     
     
         52 . The extruded aluminum alloy product of  claim 50 , wherein the L-T Klc is greater than 44 ksi √inch and the L TYS is greater than 68 ksi. 
     
     
         53 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has an electrical conductivity greater than 40.6% 1ACS. 
     
     
         54 . The extruded aluminum alloy product of  claim 1 , wherein the alloy product has an electrical conductivity greater than 41.0% 1ACS. 
     
     
         55 . A method of making an extruded aluminum alloy product of  claim 1 , the method comprising:
 homogenizing a cast billet or shape of the aluminum alloy;   hot working the billet or shape into an extruded product;   subjecting the extruded product to a solution heat treatment at a temperature of from 880 to 910° F.;   quenching the solution heat treated product;   stretching the extruded product; and   artificially aging the extruded product to at least one temperature of from 315 to 345° F. for 5 to 20 hours.