Patent ID: 8323426

Claim:
A method for producing a substantially unrecrystallized aluminum alloy plate with a thickness of at least 30 mm and up to 60 mm, said method comprising: a) casting an ingot comprising 2.2 to 3.9 wt. % Cu, 0.7 to 2.1 wt. % Li, 0.2 to 0.8 wt. % Mg, 0.2 to 0.5 wt. % Mn, 0.04 to 0.18 wt. % Zr, less than 0.05 wt. % Zn, and optionally 0.1 to 0.5 wt. % Ag, remainder aluminum and unavoidable impurities, b) homogenizing said ingot at 490°-510° C. for a duration from 4-15 hours, c) hot rolling said ingot with an exit temperature of at least 410° C. to a plate with a final thickness of at least 30 mm, d) solution heat treating by soaking at 490 to 540° C. for 15 min to 4 h, wherein the total equivalent time of homogenization and solution heat treatment t(eq) t ⁡ ( eq ) = ∫ exp ⁡ ( - 26100 / T ) ⁢ ⅆ t exp ⁡ ( - 26100 / T ref ) does not exceed 30 h, where T (in Kelvin) is the instantaneous temperature of treatment, which evolves with the time t (in hours), and T ref is a reference temperature set at 773 K, e) cold water quenching, f) stretching said plate with a permanent set from 2 to 5%, g) aging said plate by heating at 130-160° C. for 5 to 60 hours.