A Mg-Zn-Y alloy with the addition of low-cost RE（Ce

La）mischmetal was designed.Effects of RE（Ce

La）mischmetal level on microstructure evolution and mechanical properties of Mg-Zn-Y alloy at room and elevated temperature were investigated by OM

SEM

XRD and tensile testing.After adding the RE（Ce

La）mischmetal into ZW61（Mg-6Zn-1.4Y）alloy

the microstructure is refined obviously and a kind of new phase with high melting point named as T phase[（Ce

La）(Mg

1-x

Zn

x

)

11

]is precipitated from the alloy.The precipitation of the Tphase can decrease the value of Zn/Y in the residual melt and then the phase transformation can be changed.Meanwhile

the T phase presents the satisfied thermal stability which is beneficial to improving alloys’mechanical properties at elevated temperature.However

excessive T phase precipitation can lead to stress concentration and lower tensile strength at room temperature.With 1% RE（Ce

La）addition

high mechanical properties can be observed for the alloy at room temperature.In addition

the tensile strength of the alloy at elevated temperature is increased with the increased of RE（Ce

La）content.