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.ltoreq.(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.