Twins and Texture of AZ31 Magnesium Alloy Sheet Deformed by Bidirectional Cyclic Bending Technology

Bidirectional cyclic bending technology (BCBT) was used to improve the microstructure, texture and mechanical properties of AZ31 magnesium alloy sheet. Because of the exchange of compression deformation and tensile deformation caused by BCBT, microstructure evolution occurs, which is compressive deformation -> twins formation -> dynamic recrystallization -> twins disappearing -> grain refined. Fine grains of uniform distribution are formed and the properties of magnesium alloys are improved. When the deformation temperature is 483 K and deformation process is 3 passes, basal texture of AZ31 magnesium alloy sheet is weakened, texture intensity is reduced from 9.59 to 3.54, and the average grain size is 12.2 gm. When AZ31 magnesium alloy is deformed by BCBT of 1 pass at temperature 443 K, the tensile strength is 325 MPa, and the yield strength is 225 MPa. Compared with that of original billet, the tensile strength is increased by 19%, and the yield strength is increased by 28%. When AZ31 magnesium alloy is deformed by BCBT of 3 passes at temperature 483 K, the elongation is 17.1% at room temperature, which is increased by 42%.