A review of electrically assisted heat treatment and forming of aluminum alloy sheet

High-performance heat treatable aluminum alloy sheet is widely used in aircraft and automobile industries because of its excellent mechanical properties, including low density, good corrosion resistance, and high specific strength. Many heat treatment and forming methods have been developed for aluminum alloys, such as warm stamping, hot stamping in die quenching, in order to maximize the formability, and the formed strengths. Among which, electrically assisted process (EAP) becomes attractive due to its improvement of convenience, energy saving, and efficiency. Many investigations have been published in recent decades to show that the heat treatment can be accelerated and the formability can be improved due to the thermal and non-thermal effects of electric current and tried to characterize the possible mechanisms. Hence, this paper gives a comprehensive review of the effects of electric current on the heat treatment and forming of aluminum alloy from macro- and micro-aspects. Based on this, some perspectives in developing trends of EAPs are proposed, including the mechanisms of EAP, the mechanical properties under complex stress states, and the industrial applications of EAP.