Evaluation of static recrystallization and grain growth kinetics of hot-rolled AZ31 alloy

The static recrystallization/grain growth kinetics of the AZ31 (Mg-3Al-1Zn, wt%) alloy were investigated employing Vickers microhardness and electron backscatter diffraction (EBSD) measurements. was subject to a hot-rolling for 70% thickness reduction then annealed at various temperatures (150°C, 250°C, 350°C) from 5 min 24 h. First, recrystallization analysed by means Johnson-Mehl-Avrami-Kolmogorov (JMAK) model. results showed that occurred under two regimes both involving their own Avrami exponent/ activation energy. In regime I, exponent found in range 1.5-0.35 depending on annealing temperature energy 74.1±5.7 kJ×mol-1. II, an identical value (0.1-0.2) very low 14.8±0.7 kJ×mol-1 all conditions. Non-random nucleation sites such as shear bands considered main factor responsible deviation JMAK Moreover, grain well fitted general equation where . Accordingly, Qg = 109± 0.2 which is median between boundary diffusion bulk values Mg its alloys. derived energies discussed terms influencing factors solute drag, formation basal texture, microstructural heterogeneities like twinning.