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 Omega 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 Omega 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 Omega phase in deformed Al-Cu-Mg-Ag alloy. Naturally, the strength of 1% stretched Al-Cu-Mg-Ag alloy is obviously enhanced by preaging. (C) 2018 Elsevier B.V. All rights reserved.