Aluminum alloy products, such as plate, forgings and extrusions, suitable
for use in making aerospace structural components like integral wing spars, ribs
and webs, comprises about: 6 to 10 wt. % Zn; 1.2 to 1.9 wt. % Mg; 1.2 to 2.2 wt.
% Cu, with Mg(Cu+0.3); and 0.05 to 0.4 wt. % Zr, the balance Al, incidental
elements and impurities. Preferably, the alloy contains about 6.9 to 8.5 wt. %
Zn; 1.2 to 1.7 wt. % Mg; 1.3 to 2 wt. % Cu. This alloy provides improved combinations
of strength and fracture toughness in thick gauges. When artificially aged per
the three stage method of preferred embodiments, this alloy also achieves superior
SCC performance, including under seacoast conditions.