The impact of trace Y addition on the static recrystallization behavior of Mg: A quasi-in-situ EBSD study

The development of a strong basal texture during cold or thermo-mechanical processing adversely affects the mechanical performance of Mg alloys. Alloying with rare earth (RE) elements has been demonstrated to be an effective approach for weakening basal texture in deformed Mg alloys during recrystallization. Nevertheless, the underlying mechanisms responsible for texture weakening in Mg-RE alloys remain ambiguous. In this study, using a dilute Mg-0.3Y (at.%) binary alloy as a model system, we systematically investigated the static recrystallization behavior of rolled Mg-RE alloy through a quasi-in-situ electron backscatter diffraction technique. Our results reveal that the newly nucleated grains with various orientations predominately emerge within shear bands, however, the nucleation incubation period of Mg-0.3Y alloy is significantly extended compared to that of pure Mg. During the subsequent grain growth stage, the preferential growth of basal grains, commonly observed in pure Mg, is markedly inhibited in the Mg-0.3Y alloy. Due to the inhabitation of growth selection, the volume fraction of non-basal texture eventually exceeds that of the initially dominant basal texture in the deformed matrix, contributing primarily to the texture weakening. Notably, higher segregation energy at high-angle grain boundaries facilitates Y atom accumulation along grain boundaries of recrystallized grains, homogenizing and reducing interfacial energy, which thermodynamically enables the sluggish grain growth. The direct visualization of static recrystallization behaviors offers critical insights into texture evolution mechanisms of deformed Mg-RE alloy and provides fundamental guidance for developing highly formable Mg alloys through grain boundary engineering.