Unveiling annealing texture formation and static recrystallization kinetics of hot-rolled Mg-Al-Zn-Mn-Ca alloy

The development of Mg-Al-Zn-Mn-Ca series alloys provides a potential prospect to achieve high strength and formability at room temperature (RT). The formation of elliptical annular texture is treated as a crucial factor for the enhanced RT formability. However, the origin of such an elliptical annular texture formation has been rarely reported. Herein, we unveiled the formation and evolution of elliptical annular texture in the hot-rolled Mg-1.6Al-0.8Zn-0.4Mn-0.5Ca (AZMX1100, wt.%) alloy after annealing at different temperatures for 1 h, and its static recrystallization (SRX) kinetics in given annealing temperature for different time. The results revealed that the formation of elliptical annular texture in the hot-rolled AZMX1100 alloy after annealing was derived from nucleation-oriented SRX mechanism, which took place in 200-300 degrees C, induced by cracked chain-shaped Al2Ca phases, contraction twins, intersections of double twins, intersections of double twins and grain boundaries and non-basal slips. On further annealing from 300-450 degrees C, the grains with 45 degrees -70 degrees transverse direction (TD) preferentially grew, which made elliptical annular texture extended along the TD. Based on the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model, Avrami exponent n value was estimated to be 0.68-1.02, attributed to non-random SRX nucleation, giving rise to the lower activation energy Q(R) of nucleation of similar to 74.24 kJ/mol. Since the co-segregation of Al, Zn and Ca atoms in grain boundaries created a strong interaction of solutes and grain boundaries, the hot-rolled AZMX1100 alloy exhibited the higher activation energy Q(g) (similar to 115.48 kJ/mol) of grain growth. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.