The influence of preaging on the strength and precipitation behavior of a deformed Al-Cu-Mg-Ag alloy

It is well known that deformation prior to artificial aging considerably decreases the strength properties of Al-Cu-Mg-Ag alloys by suppressing the formation of the main strengthening Ω precipitates. This negative effect is the as-yet unresolved obstacle for the wide applications of Al-Cu-Mg-Ag alloys. In this work, preaging prior to deformation is conducted to evaluate its possible influence on improving the typical microstructure and strength of deformed Al-Cu-Mg-Ag alloy. Quantitative transmission electron microscopy (TEM) and atom probe tomography (APT) analysis of the initial solute clustering and subsequent Ω precipitation of the deformed alloy with and without preaging indicate that preaging ensures strong Mg-Ag co-clustering and hence benefits the dense precipitation of Ω phase in deformed Al-Cu-Mg-Ag alloy. Naturally, the strength of 1% stretched Al-Cu-Mg-Ag alloy is obviously enhanced by preaging.