Microstructures and mechanical properties of high strength Mg-Zn-Mn alloy

The microstructures and mechanical properties of a new Mg-6%Zn-1%Mn (mass fraction) wrought magnesium alloy were studied, which could be extruded smoothly at 310–330 °C with a complete dynamic recrystallization. After solution treatment one and two-step aging techniques were used. All as-aged microstructures contained two types of dispersed phases: β' phases and pure α-Mn particles. The two-step aging had a better strengthening effect than the traditional one-step aging, and the strength value achieved by the two-step aging could reach that of the ZK60 wrought magnesium alloy. The outstanding precipitation strengthening effect of the alloy should be attribute to the GP zones, diffusive solute-rich zones and some metastable phases formed during the first step aging that provide more effective nuclei for Mg-Zn strengthening phases during the second step aging.