Microstructure and mechanical properties of extruded Mg96Zn1Y3 alloy

Microstructure and mechanical properties of an extruded Mg96Zn1Y3 alloy have been investigated in the current study. Microstructure of as extruded alloy consists of α-Mg, long period stacking ordered (LPSO) phase and parallelepiped Y-riched phases, which exhibits a bimodal distribution of fine recrystallized and coarse elongated grains. Fine recrystallized grains with an average grain size of 1.5 μm are mainly pinned by bulk LPSO-14H phase, inside which both LPSO-18R phase and LPSO-14H phase coexist. The extruded Mg96Zn1Y3 alloy exhibits a good combination of yield strength and elongation below 200 °C, which is mainly attributed to LPSO phases, stronger texture and finer DRX grains. The main deformation is controlled by load transfer mechanism below 250 °C, and deformation is controlled by non-basal dislocation movement between 300 °C and 325 °C. A good plasticity is attained at 350 °C with an elongation of 140%. The flow stress behavior at 350 °C is mainly controlled by non-basal slip accompanying with dynamic recrystallization and growth of grain.