EVOLUTION OF MICROSTRUCTURE DURING RECRYSTALLIZATION OF MAGNESIUM ALLOYS

Abstract

Micro-structural evolution during the annealing of cold rolled Mg, Mg-1.5 normal direction and Mg-3Y sheets has been examined. The experimental results show a significant difference in recrystallization kinetics and grain growth between pure Mg and Mg-rare-earth alloy sheets. Pure Mg sheet shows rapid recrystallization and grain growth, whereas recrystallization is considerably retarded in the Mg-rare-earth alloys. Although recrystallized grains which are triggered at shear bands in the cold rolled pure Mg sheet show a relatively weak texture with a basal pole split into the sheet rolling direction, rapid grain growth is accompanied by re-strengthening of the basal-type texture. In contrast, a weak texture appears in the early recrystallization stage in Mg-rare-earth alloys and is retained during annealing due to retarded recrystallization and grain growth.