On the recrystallization behavior of homogenized AZ81 magnesium alloy: The effect of mechanical twins and γ precipitates

The present study deals with the recrystallization behavior of homogenized AZ81 magnesium alloy with emphasizing on the role of mechanical twins and γ precipitates. Towards this end a set of hot compression tests were conducted in the temperature range of 250-450 °C under strain rates of 0.003, 0.03 and 0.3 s−1. The results indicate that the dynamic recrystallization (DRX) has been occurring in the large scales thereby considered as the main factor affecting the related flow stress characteristics. The twin related dynamic recrystallization (including DRX within twin bands and DRX at twin-twin intersections) possesses a great contribution to the formation of new recrystallized grains. The obtained results also confirm that the dynamic precipitation of γ phase has a significant effect on hindering the growth of new DRX grains thereby resulting in an outstanding grain refinement. The role of mechanical twinning and dynamic precipitation on the DRX behavior of the alloy is more pronounced at higher and lower Zener-Hollomon parameter, respectively.