Microstructure evolution of AZ31B magnesium alloy sheets deformed in different deformation directions

Based on the in-plane tension and compression tests of AZ31B magnesium sheets at temperature of 200-300 °C and strain rate of 0.001-0.1 s−1, the microstructure evolution was investigated. The results show that when the sheets are stretched above 200 °C, the {101̅1} contraction twin (CT) is not activated, but many tiny {101̅2} extension twin (ET) particles are formed, inducing secondary recrystallization. When the sheets are compressed below 250 °C, the grains may rotate several times by ET because of the diversity of grain orientation and the compatible deformation, causing the basal texture deviated about 30° from normal direction (ND). When the sheets are compressed at 300 °C, the ET particles also induce large secondary recrystallization grains. Furthermore, the dynamic recrystallization (DRX) mode is continuous dynamic recrystallization (cDRX), whose texture is controlled by the initial texture, the dominant activated slip systems and the deformation, and the misorientation angle Chi-Square (χ2) distributes with the density peak in 25-35°.