On the mechanical properties and stress corrosion resistance of ternary AlCuLi and Quaternary AlLiCuMg alloys

Abstract

Two Al-2.1wt.%Li alloys, one with a 2.2 wt.% Cu addition, and the other containing 1.1 wt.% Cu and 0.7 wt.% Mg, were evaluated for mechanical properties and stress corrosion resistance. At the same strength level, both alloys were found to have equal ductilities, but the quaternary alloy had a superior toughness. Higher toughness correlated with macroscopically rougher fracture surfaces, but localized ductility in brittle materials gave the appearance of microscopic toughness. Both alloy systems were shown to have a poor resistance to stress corrosion crack initiation and propagation.