Microstructures and mechanical properties of extruded Mg–2Sn–xYb (x=0, 0.1, 0.5 at.%) sheets

Microstructures and mechanical properties of extruded Mg–2Sn–xYb (x = 0, 0.1, 0.5 at.%) sheets were investigated. The grain size of as-cast Mg–2Sn alloy is significantly reduced with increasing Yb concentration. In addition to α-Mg and Mg2Sn phase, some fine Mg2(Sn,Yb) particles are observed in as-cast Mg–2Sn–0.5Yb alloy, but these fine particles are not observed in as-cast Mg–2Sn–0.1Yb alloy due to a high solubility of Yb in Mg matrix. Tensile tests demonstrated that extruded Mg–2Sn–0.5Yb sheet exhibited the highest tensile strength and available elongation to failure at room temperature, while extruded Mg–2Sn–0.1Yb alloy exhibited the highest tensile properties at 100 °C and 200 °C. The difference in the tensile properties of extruded sheets mainly arises from the different strengthening roles of grain refinement, solid solution strengthening and precipitation strengthening of particles.