Deformation behavior of AZ31 Mg alloys sheet during large strain hot rolling process: A study on microstructure and texture evolutions of an intermediate-rolled sheet

Commercial AZ31 Mg alloys sheet was hot rolled by 50% thickness reduction in a single pass. The rolling process was manually interrupted before the entire sheet was rolled, and an intermediate-rolled sample was obtained. The microstructure, texture and mechanical responses on both surface and mid-layer of the intermediated-rolled sample were investigated. Our results show that the thickness gradients of microstructure and texture of as-rolled sheet were mainly caused by heterogeneously severe deformation when the surfaces of the sheet were bitten by the rollers. Both discontinuous and shear bands related dynamic recrystallization were observed. The recrystallized grains inside shear bands first nucleated in twins. The refined grains exhibited a strong basal texture with random distribution of 〈112¯0〉 direction. Discontinuous release of deformation strain during hot rolling led to strain flow localization, which resulted in formation of shear bands. Shear bands helped to coordinate the strain distribution between two nearby regions to prevent cracking in large strain rolling.