Influence of Er addition and extrusion temperature on the microstructure and mechanical properties of a Mg-Zn-Zr magnesium alloy

► Er addition inhibited the formation of divorced Mg-Zn binary eutectics. ► Er addition led to the formation of thermal stable Mg-Zn-Er intermetallics. ► Er was found to promote homogenous deformation and recrystallization. ► Er effectively suppressed grain growth at extrusion temperature as high as 420 °C. ► A solid solution softening effect of Er was found to be responsible for enhanced elongation with Er addition.