Improvement of mechanical properties and thermal stability of Al–Cu–Mg–Ag alloy by warm rolling

Abstract

In this paper, the microstructure, mechanical properties and thermal stability of Al–Cu–Mg–Ag alloys processed by warm rolling were compared with cold rolling with same strains using scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM), and the strengthening mechanism has been quantitatively investigated. The mechanical properties of the Al–Cu–Mg–Ag alloy are significantly improved by warm rolling at 200 °C and subsequent artificial aging at 180 °C, both before and after heat exposure at 200 °C for 100 h. Microstructure investigations revealed that compared to cold-rolled samples, warm-rolled samples have a higher number density of Ω plates after artificial aging, and the increase in yield strength caused by precipitation strengthening is greater. After heat exposure at 200 °C for 100 h, although the Ω plates in the warm-rolled samples are coarser compared to the cold-rolled alloys, the number densities are higher. Therefore, warm-rolled samples exhibit better mechanical properties than cold-rolled samples.