On the thermodynamics and kinetics of electropulsing induced dissolution of β-Mg17Al12 phase in an aged Mg–9Al–1Zn alloy

Electropulsing induced dissolution of β-Mg17Al12 phase was investigated using scanning electron microscopy, X-ray diffraction and hardness tests. It was found that compared with conventional heat treatment, electropulsing treatment (EPT) decreased the apparent solid solution temperature of the β phase and accelerated the dissolution of β phase into α-matrix in a very short time of several seconds due to reduction of the nucleation thermodynamic barrier and enhancement of atomic diffusion, respectively. A model for the temperature field of a strip under EPT was established. Based on the contributions of the coupling of the thermal and athermal effects with the free energy and the direct electron–atom interactions, the thermodynamics and kinetics of the electropulsing induced dissolution of β-Mg17Al12 are discussed.