Abstract: Dispersoids 7xxx aluminum alloy products with enhanced fatigue crack growth deviation and Environmentally Assisted Cracking (EAC) resistance are disclosed. The 7xxx aluminum alloy comprises 1 to 3 wt. % Cu, 1.2 to 3 wt. % Mg, 4 to 8.5 wt. % Zn, up to 0.3 wt. % Mn, up to 0.15 wt. % Zr, up to 0.3 wt. % Cr dispersoid elements, incidental elements, and the balance Al. In one embodiment, the alloy includes Zr + Cr + Mn in the range of 0.2 to 0.8 wt. %. In another embodiment, the alloy includes Zr + Mn in the range of 0.07 to 0.7 wt. %. This alloy can be fabricated to plate, extrusion, or forging products, and is especially suitable for aerospace structural components. The products have enhanced EAC resistance and fatigue crack growth deviation resistance. Meanwhile, the products have an excellent combination of strength, fracture toughness, ductility at different orientations, and Stress Crack Corrosion (SCC), and exfoliation corrosion resistance suitable for aerospace application.

Abstract: High strength and high fracture toughness 7xxx aluminum alloy products comprise 6.5 to 7.2 wt. % Zn, 1.55 to 1.95 wt. % Cu, 1.75 to 2.15 wt. % Mg, 0.095 to 0.15 wt. % Zr, incidental elements, and the balance Al. In one embodiment, the aluminum alloy product includes Mg/Cu and Zn/Mg ratios in the range of 1.05 to 1.35, and 3.2 to 4.0, respectively. This aluminum alloy product can be fabricated to produce plate, extrusion or forging products, and is especially suitable for aerospace structural components. The products have an excellent combination of strength, fracture toughness, Kmax at the fatigue crack deviation point, ductility in different orientations, and corrosion resistance suitable for aerospace application.