DAMAGE TOLERANT ALUMINUM ALLOY SHEET FOR AIRCRAFT SKIN

摘要

Disclosed is a method of producing a sheet product having improved levels of toughness and fatigue crack growth resistance while maintaining high strength, comprising providing a body of an aluminum base alloy containing 9.0 to 4.5 wt.% Cu, 1.2 to 1.5 wt.% Mg, 0.4 to 0.6 wt.% Mn, 0.12 wt.% max. Fe, 0.05 wt.% max. Si, the remainder aluminum, incidental elements and impurities and heating a body of the alloy to above 910.degree.F to dissolve soluble constituents. Thereafter, the body is hot rolled in the range of about 600 to 900.degree.F, solution heat treated for a time of less than about 15 minutes at a solution heat treating temperature, and rapidly cooled and naturally aged to provide a sheet product with improved levels of fatigue crack growth resistance while maintaining high strength.