Texture Evolution and Serrated Failure of Az31b Alloy Subjecting to Equal Channel Angular Extrusion

Abstract

Equal channel angular extrusion (ECAE) is considered the most promising method for improving strength and ductility. The microstructures after ECAE have been extensively studied for Mg alloys relating to mechanical properties. However, the changes in texture and their relationship with the prior conditions, extrusion conditions and extrusion directions are rarely studied. In the current work, the changes in texture of AZ31B Mg alloys were investigated along the ND, TD, and RD after ECAE processing one pass. The results revealed a rule that the AZ31B alloy follows for texture changes, where the basal texture (namely the focused c-axis) orients 45º or nearly orients 45º, regardless of the pre-extrusion texture, extrusion temperature, and extrusion rate. Interestingly, serrated failure sorely occurs along the ND for all extrusion conditions, due to the basal slip in an unfavorable orientation and the shear plane not parallel to either pyramidal slip directions.

Keywords: Keywords: Serrated failure, c-axis orients 45º, Mg alloy, ECAE, Texture