Electropulsing-driven rapid reversible phase transformations in Al-Mg-Si-Cu alloys

Abstract

The electrical free-energy term, ΔGe, has been widely used to rationalize electropulsing-driven ultrafast precipitation and homogenization in age-hardenable alloys. However, its quantitative contribution relative to enhanced kinetics to phase transformation remains unclear. Here, we demonstrate reversible phase transformations in Al-Mg-Si-Cu alloys controlled by current density. With frequency and single electric pulse duration fixed, lower current densities promote ultrafast precipitation in solution-treated samples, whereas slightly higher current densities drive rapid precipitates dissolution in peak-aged samples. These findings suggest that ΔGe may not be the dominant factor determining the transformation direction, underscoring the importance of kinetic effects during electropulsing.