Grain Refinement in a Mg AZ91 Alloy via Large Strain Hot Rolling

Abstract

Significant grain refinement has been achieved in a cast Mg-based AZ91 alloy via large strain hot rolling. This is a simple processing method consisting of one rolling pass at intermediate temperatures with a large thickness reduction. The as-cast material was first homogeneized in order to obtain a homogeneous and equiaxed grain structure with a random texture. During processing, a double-peak basal texture develops, typical of rolled Mg alloys, that results from the operation of basal, prismatic and pyramidal ⟨c+a⟩ slip. The stabilization of this deformation texture during rolling suggests that the mechanism for grain refinement is continuous dynamic recrystallization.