Effect of electropulsing treatment on microstructure and mechanical behavior of Ti-6Al-4V alloy sheet under argon gas protection

The effect of electropulsing on microstructure and mechanical behavior of Ti-6Al-4V alloy sheet was studied by the electropulsing treatment tests under argon gas protection. Compared to conventional treatment test without current, the specimen tensile strength keeps constant and the maximum plasticity increases by 21.67% with current density of 17.8 A/mm2 under electropulsing treatment. An empirical model to predict the temperature evolution of Ti-6Al-4V sheet under electropulsing was established. To understand the mechanism of electropulsing treatment, the microstructure of electropulisng treated specimens was analyzed. The results show that the electropulsing can accelerate the recrystallization and phase transformation of Ti-6Al-4V under a relatively low temperature compared to heat treatment. The enhancement of elongation at 17.8 A/mm2 is attributed to rapid recrystallization. Based on the contribution of thermal and athermal effect on thermodynamics and kinetics, the mechanism of the electropulsing on the recrystallization and phase transformation are discussed.