Patent ID: 8557062

Claim:
A method of producing a copper-free aluminum alloy wrought product, the method comprising: (a) providing a molten body of an aluminum base alloy comprised of about 0.01 to about 1.5 weight percent silver; about 1.0 to about 3.0 weight percent magnesium; about 4.0 to about 10.0 weight percent zinc; about 0.05 to about 0.25 weight percent zirconium; a maximum of 0.15 weight percent iron; a maximum of 0.15 weight percent silicon; and a remainder including aluminum, incidental elements, and impurities, wherein the remainder does not include copper and scandium, and wherein a sum of the zinc and the magnesium and the silver in the molten body ranges from about 9.5 weight percent to about 11.5 weight percent; (b) casting the molten body of the aluminum base alloy to provide a solidified body; (c) homogenizing the solidified body; (d) extruding, rolling or forging the solidified body to produce a wrought product; (e) solution heat treating the wrought product in a temperature range of about 870° F. to about 900° F. for about 5 to about 120 minutes; (f) cold working the wrought product, wherein the cold working comprises cold rolling 0% to 22% or cold compressing between 0.2% and 3.5%; and (g) artificially aging the wrought product, wherein the solidified body and the wrought product are not heat treated above 932° F., and wherein a fracture toughness for the aged wrought body is at least 40 ksi square root inch, and wherein an exfoliation corrosions resistance for the aged wrought body is ASTM rating EA or better, and wherein an electrical conductivity for the aged wrought body is at least 45% ACS.