Compressive Mechanical Anisotropy Evolution in Pretwinned AZ31 Mg Alloy upon Annealing

Pretwinning followed by annealing was employed to modify the microstructure and texture of an AZ31 wrought magnesium alloy. A precompression step was applied to an as-rolled plate to introduce dense extension twin bands, after which annealing at 300 °C for 5, 15, and 60 min was conducted. The resulting microstructures were analyzed in terms of grain size, recrystallization behavior, and texture evolution. Mechanical properties were evaluated using uniaxial compression tests along the rolling, transverse, and normal directions to quantify changes in mechanical anisotropy. The results show that this thermomechanical treatment effectively reduces yield strength anisotropy through twin-assisted recrystallization and texture randomization. The mechanical response is interpreted based on microstructural changes and the activation of twining and slip systems.