Effect of pre-precipitated micro-sized β-Mg5RE on dynamic recrystallization of hot-compressed Mg-Gd-Y-Zn-Zr alloy

• Pre-precipitated micro-sized β-Mg₅RE phases significantly enhance dynamic recrystallization (DRX) via particle-stimulated nucleation (PSN), leading to reduced flow stresses. • The activation of PSN requires synergistic interaction between β-Mg₅RE phases and grain boundaries, challenging the conventional understanding of their independent role. • The enhanced PSN-DRX in the aged alloy results in a higher fraction of DRXed grains and consequently a weaker basal texture. Micro-sized β-Mg 5 RE was precipitated by pre-aging treatment at 300°C for 52 h. To study the effect of β-Mg 5 RE on the dynamic recrystallization (DRX) of Mg-Gd-Y-Zn-Zr alloy, the aged alloy with pre-precipitates and the solution-treated alloy without pre-precipitates were compressed under different temperatures and strain rates, with a constant compression strain of ε = 0.7. The results show that the micro-sized β-Mg 5 RE precipitates within the grain and at the grain boundary could accelerate DRX softening through particle-stimulated nucleation of DRX (PSN-DRX) during compression, leading to a smaller peak strain ε p , smaller critical strain ε c , lower peak stress and higher volume fraction of DRXed grains in the aged alloy. In contrast to the previous theory regarding the independent activation of PSN-DRX by the micro-sized phase, these micro-sized pre-precipitates must work together with the grain boundaries, including the original and newly formed grain boundaries, to fulfill the activation of PSN-DRX. The presence of {10-12} tension twins after hot compression strengthened the basal textures of both alloys. Because of the higher volume fraction of DRXed grains in the aged alloy, the basal texture was weaker than that of the solution-treated alloy.