The formation of the cross shear bands and its influence on dynamic recrystallization and mechanical properties under Turned-Reverse Rolling

Abstract

Two rolling routes, traditional forward rolling (FR) and turned-reverse rolling (TRR, with tilting angle of 180° along transverse direction (TD)) were performed on AZ31B magnesium (Mg) alloy sheets. Different morphologies of shear bands and its influence on the dynamic recrystallization (DRX) and mechanical properties were investigated. The shear bands (SBs) in the FR and TRR samples show variant morphologies due to the different shear patterns. Especially, the cross shear stress results in a higher number fraction of discontinuous DRXed (DDRXed) grains with random orientation in the TRR sample, contributing to the weakening of {0001} basal texture, while continuous DRX (CDRX) dominates in the FR route, where most of DRXed grains inherit the parent orientation. Furthermore, the TRR sample shows a larger total elongation value (>35 %) than that of the FR sample without sacrificing the strength (∼275 MPa), which can be attributed to not only a more homogeneous strain in the cross SBs (CSRs) but also the activation of non-base slip in the DDRXed grains.