Microstructure evolution and mechanical properties of rolled Mg-4Zn-0.5Er-1Y alloy sheets with annealing at 200

3

80℃ for 0.5

4

h were investigated. It is found that distinct dynamic recrystallization grain with fine size can be observed in the annealed alloy sheets. Amounts of secondary phase containing RE exist in the matrix alloy

which are broken into fine particle after hot rolling to promote the heterogeneous nucleation of dynamic recrystallization grain. Strength of the alloy sheet after annealing treatment is decreased with the obvious improvement of plasticity. The alloy sheet with approximately 8 μm in size exhibits desirable mechanical properties with annealing at 350℃ for half hour

such as tensile strength of 276MPa and elongation of 22.5%. Activation energy of grain boundary migration reaches 22.76kJ/mol. In addition

kinetics model of dynamic recrystallization grain growth was established.