Heterogeneous strain-driven dynamic recrystallization behavior of Mg–Y-Nd-Zr-Gd alloy: A quasi in-situ investigation

Dynamic recrystallization (DRX) plays an important role during the high-temperature deformation of magnesium alloys, significantly influencing the microstructure and texture. Gaining insights into the DRX evolution mechanism is crucial for predicting microstructure evolution. This research utilized the quasi in-situ hot compression experiment conducted at 500 °C to monitor and analyze the DRX behavior of the Mg–Y-Nd-Zr-Gd alloy. Findings show that DRX in the early stages is predominantly driven by grain boundary (GB) migration. It was observed that GB migration tends to follow a reverse-energy direction, moving from zones with lower strain energy toward higher strain energy regions. Additionally, the heterogeneous strain distribution has proved crucial in determining the trajectory of boundary movements and influencing the dynamics of low-angle grain boundary (LAGB) evolution. Strain localization in heterogeneous regions promotes crystal rotation, and the activation of multiple slip systems within these regions serves as a key intrinsic factor contributing to variations in rotational behavior. As deformation advances, the transformation of LAGBs into high-angle grain boundaries (HAGBs) is facilitated by accumulated strain within localized heterogeneous zones, which either accelerates crystal rotation or generates pronounced orientation differences between newly recrystallized grains and their parent grains.