The effect of twinning on dynamic recrystallization behavior of Mg-Gd-Y alloy during hot compression

The effects of twinning on the dynamic recrystallization (DRX) of the Mg-6.58Gd-5.7Y-0.55Zr alloy were investigated through uniaxial compression tests at 400 °C and 450 °C with an initial strain rate of 0.001–0.1 s⁻¹ and were characterized through optical microscopy (OM), scanning electron microscopy (SEM), electron back-scattering diffraction (EBSD) and transmission electron microscopy (TEM). At a relatively high strain rate, extension twins can mainly be activated during the initial stage of hot compression, and the subsequent DRX is closely related to the twin-twin and twin-dislocation interactions. The intersected twin boundaries of the extension twins from multiple twin variants may provide effective DRX sites and promote microstructure refinement. However, extension twins from a single twin variant pair may quickly grow, soon swallowing the matrix and decreasing the DRX efficiency.