Patent ID: 8043445

Claim:
An aluminium alloy wrought product with high strength and fracture toughness and high fatigue resistance and low fatigue crack growth rate, said alloy consisting of, in weight %: Cu and Mg in a range which falls within a graphical box defined by the corner points: Corner point A is 0.45 wt % Mg, 5.35 wt. % Cu, Corner point B is 0.75 wt % Mg, 5.35 wt. % Cu, Corner point C is 0.75 wt % Mg, 5.0 wt. % Cu, Corner point D is 0.45 wt % Mg, 5.20 wt. % Cu, Fe <0.20, Si <0.20, Zn about 0.38 to <0.4, Ag 0.32-0.48, and Mn in a range of 0.15 to 0.31 and Cr in a range of 0.05 to 0.30 as dispersoid forming element elements in combination with one or more optional dispersoids forming elements selected from the group consisting of: Sc <0.7, Hf <0.3, Ti <0.4, V<0.4, and the balance being aluminium and other impurities or incidental elements, wherein the alloy is substantially free of Zr.