Dynamic recrystallization behavior of as-cast AZ91 magnesium alloy during hot compressive

Abstract

This work systematically studies the dynamic recrystallization (DRX) behavior of as-cast AZ91 magnesium alloy under hot compression deformation at 350 °C. These results were also compared with the former results obtained at 300 °C in order to evaluate the effect of deformation temperature on DRX behavior of as-cast AZ91 alloy. The results show that the “{10–12} extension twin DRX” in original grains, “original grain boundary bulging (BLG) accompanied by progressive lattice misorientation” at the original grain boundaries and “particle-stimulated nucleation (PSN)” around massive eutectic β phases are observed during compression at 350 °C. The DRX mechanism of as-cast AZ91 alloy during hot compression at 350 °C is continuous DRX. Compared with the hot compression at 300 °C, the main twin type changes from 38° {10–11}–{10–12} double twin (300 °C) to 86° {10–12} extended twins (350 °C) at the beginning of hot compression (ε = 10%). And the 30° {10–11}–{10–12} double twin forms in the sample compressed at 350 °C with further compressive strain (ε = 20%). The DRX grain size and DRX volume fraction increase after hot compression at 350 °C compared with hot compression at 300 °C.