Microstructure Evolution and Mechanical Behavior of AZ31 Magnesium Alloy Sheet with Bimodal Texture under Bending Deformation

Three-point bending tests were conducted on AZ31 magnesium alloy sheets with a bimodal texture. The results indicate that there is a significant strain gradient in the thin sheets during three-point bending, with the extrados under tensile stress and the intrados under compressive stress. Plastic deformation is mainly coordinated by twinning. The volume fraction of {10-12} extension twins (ETs) activated on the extrados of the RD sample is higher than that on the intrados, and this difference becomes more pronounced as the strain increases to 9%. The compressive stress on the intrados of the TD sample is nearly perpendicular to the grain c-axis. Most {10-12} extension twin (ET) variants with TD orientation have higher values of Schmid factor during loading. The low SF ET variants are activated by the local strain accommodation between the twins and the slip systems.