Effect of pulsed current density on creep-aging behavior and microstructure of AA7150 aluminum alloy

Abstract

High pulsed current density has both thermal and athermal effects on the metals, meaning that it can be used to promote the metal forming efficiency. Additionally, it can also be used in the creep-ageing forming of high-strength aluminum alloys. In this present study, the creep-aging behavior, mechanical properties, and microstructural evolution were investigated at various current densities of AA7150 aluminum alloy. The results have shown that the electropulsing treatment (EPT) can increase the dislocation movement and decrease the dislocation density for the coupling of thermal and athermal effects. As such, it could improve both the creep rate and strain by increasing the pulsed current density. Compared with the creep aging at 0 A/mm2, the average grain size at 8 A/mm2 decreased from 15.3 μm to 11.6 μm. The EPT can increase the atom diffusion rate, leading to the precipitation and growth of η′ phase. Additionally, due to the thermal effect variations at different current densities, the effect of temperature was studied both via simulation and experimentally.