Abstract: Aluminum alloy products about 4 inches thick or less that possesses the ability to achieve, when solution heat treated, quenched, and artificially aged, and in parts made from the products, an improved combination of strength, fracture toughness and corrosion resistance, the alloy consisting essentially of: about 6.8 to about 8.5 wt. % Zn, about 1.5 to about 2.00 wt. % Mg, about 1.75 to about 2.3 wt. % Cu; about 0.05 to about 0.3 wt. % Zr, less than about 0.1 wt. % Mn, less than about 0.05 wt. % Cr, the balance Al, incidental elements and impurities and a method for making same. The invention alloy is useful in making structural members for commercial airplanes including, but not limited to, upper wing skins and stringers, spar caps, spar webs and ribs of either built-up or integral construction. The invention alloy may be aged by 2 or 3 step practices while exceeding the SCC requirements for applications for which the invention alloy is primarily intended.

Abstract: Aluminum alloy products about 4 inches thick or less that possesses the ability to achieve, when solution heat treated, quenched, and artificially aged, and in parts made from the products, an improved combination of strength, fracture toughness and corrosion resistance, the alloy consisting essentially of: about 6.8 to about 8.5 wt. % Zn, about 1.5 to about 2.00 wt. % Mg, about 1.75 to about 2.3 wt. % Cu; about 0.05 to about 0.3 wt. % Zr, less than about 0.1 wt. % Mn, less than about 0.05 wt. % Cr, the balance Al, incidental elements and impurities and a method for making same. The invention alloy is useful in making structural members for commercial airplanes including, but not limited to, upper wing skins and stringers, spar caps, spar webs and ribs of either built-up or integral construction. The invention alloy may be aged by 2 or 3 step practices while exceeding the SCC requirements for applications for which the invention alloy is primarily intended.

Abstract: This invention describes a method of producing a flat aluminum sheet product by providing an aluminum alloy stock, hot working the aluminum alloy stock through preheating and hot rolling, side sawing the aluminum alloy stock, subjecting the aluminum alloy stock to solution heat treatment, cold rolling the aluminum alloy stock to reduce its thickness by about 0.25% to about 5%, and finally stretching the aluminum alloy stock.