Enhanced mechanical properties in an Al–Cu–Mg–Ag alloy by duplex aging

A type of duplex aging heat treatment was developed to improve the mechanical properties at room temperature and elevated temperatures in a pre-strained Al–Cu–Mg–Ag alloy. In contrast to the conventional T8 temper at 165 °C and 200 °C, the hardening response of the alloy to aging was increased by duplex aging treatment, the ultimate tensile strength and yield strength of duplex aging temper were improved by approximately 3–7%, which was attributed to the fact that the recovery of dislocations occurred and the precipitation of θ′ phase was restrained effectively at high aging temperature, and more Ω precipitates were formed during secondary aging.