Direct observation of annealing-driven recrystallization behavior in magnesium alloy at low strain condition

• The bimodal texture evolution mechanism of AZ31 magnesium alloy during the thermos-mechanical process is revealed. • The competition between the matrix and the tensile twin in the pre-deformed magnesium alloy during heat treatment is systematically investigated. • Regardless of the boundary type or boundary energy, strain-induced boundary mobility depends mainly on the energy differences across the boundary with a tendency to move towards the side with higher stored energy. Grain-twin interactions are significant in texture modification under thermodynamic driving force. In this study, annealing-driven twinning/detwinning behavior, grain growth, and corresponding texture evolution in a pre-deformed AZ31 magnesium alloy were systematically tracked and investigated via in-situ heating synchrotron X-ray diffraction and quasi in-situ electron backscattered diffraction techniques. A twinning texture is generated in the pre-deformed sample due to the activation of {10 1 ‾ 2} tensile twinning. During annealing, dislocation annihilation occurs between 100 and 280 °C, and recrystallization occurs above 280 °C, manifesting as the initial residual matrix and twins being competitively swallowed by each other, forming a bimodal texture. The recrystallization process is completed by boundary movement, which depends on the energy difference across the boundary. In addition, it is found that the grain boundaries favor movement towards the side with higher stored energy, regardless of the boundary type or the boundary energy.