The microstructure and mechanical properties of the Mg-10Er-2Zn-0.6Zr alloy were investigated by means of optical microscope（OM）

X-ray diffraction（XRD）

scanning electron microscope（SEM）and mechanical tests.The results reveal that as-cast Mg-10Er-2Zn-0.6Zr alloy is mainly composed ofα-Mg dendrite and interdendritic long period stacking ordered（LPSO）phases and Mg

3

（Er

Zn）phases.After solution treatment at 500℃for 20 h

both LPSO phase and Mg

3

（Er

Zn）disappear and in turn a new W（Mg

3

Er

2

Zn

3

）phase can be observed along the grain boundaries.During the following cooling in the furnace to 400 ℃

the LPSO lamella structure is parallel to each other precipitated within and throughout theα-Mg grains.The solution-treated alloy exhibits the desirable mechanical properties

where yield strength

tensile strength and elongation reach 117 MPa

227MPa and 17.9%

respectively.However

the compressive properties are superior to those of tensile ones.