Influences of pre-aging precipitates on static recrystallization behavior of Mg–6Al–1Zn alloy

Due to the dynamic evolution of precipitates during thermomechanical processing, the intricate effects of second-phase particles on recrystallization behavior are still far from being clear. In this work, the relevance between static recrystallization and pre-aging precipitates in AZ61 (Mg–6Al–1Zn) alloy was systematically investigated. Our results reveal that the presence of pre-aging precipitates increases stored deformation energy by facilitating the generation of dislocations, thus accelerating the recrystallization rate during the initial recrystallization stage. Besides, these uniform distributed dislocations could act as heterogeneous nucleation sites and promote precipitation of fine dispersoids during the subsequent annealing stage. These dispersoids hinder the movement of dislocations and grain boundaries, leading to the increase of Zener pinning pressure. Therefore, the effect of pre-aging particles on recrystallization kinetics gradually transforms from acceleration to retardation as the annealing time prolongs. This work demonstrates that manipulating the features of precipitates through pre-aging treatment is an applicable strategy to control the static recrystallization behavior of Mg alloys.