Different annealing behaviours of warm rolled Mg-3Al-1Zn alloy sheets with dynamic recrystallized microstructure and deformation microstructure

摘要

The annealing behaviours of Mg-3Al-lZn magnesium alloy sheets warm rolled at 225 ℃ and 150 ℃ using differential speed rolling, which are mainly characterized by dynamic recrystallized microstructure and deformation microstructure, respectively, were investigated at different annealing stages. Static recrystallization occurs for the sheet rolled at 150 ℃ while only grain growth proceeds for the sheet rolled at 225 ℃ For the sheet rolled at 225 ℃, the grain growth of dynamic recrystallized grains eliminates the basal pole inclination in the rolling direction. In contrast, for the sheet rolled at 150 ℃, the grain growth after static recrystallization retains the basal pole inclination, which is favoured for sheet forming. This difference in texture evolution may be attributed to the dynamic or static recrystallization prior to grain growth, which results in residual dislocation densities for the former and thus leads to the preferential growth of harder oriented basal grains at the centre of (0001) pole figure with lower dislocation densities during annealing.