Plastic deformation of AZ31B magnesium alloy in the preform and electropulsing treatment process

Abstract

Magnesium alloys exhibit poor formability at room temperature owing to their hexagonal close-packed crystal structure. In this study, a multi-step preform and electropulsing treatment method was applied to the plastic deformation of AZ31B magnesium alloy to improve its cumulative ductility. The mechanical properties, microstructure, and dislocation evolution were investigated using various parameters. The cumulative elongation of all specimens increased significantly, with the maximum approximately twofold higher for the initial specimens. Although the yield strength decreased after the first step, it increased with the following steps. After electropulsing treatment, the specimens were recrystallized and the dislocations were annihilated. The deformed microstructure caused by preform recovered and the recovery degree was associated with the preform and electropulsing treatment parameters. Therefore, the preform and electropulsing treatment method is effective to enhance the ductility of AZ31B magnesium alloy at room temperature, and a set of appropriate pulse current parameters can achieve satisfactory strength and elongation results. Moreover, the effect of the pulse current on the dislocation mobility and climb mainly accounts for the beneficial restoration during the preform and electropulsing treatment process.