The microstructure and mechanical properties of Mg-8 Zn-1 Ag-0.7 Zr alloy were investigated by OM、SEM and tensile testing. The experimental results reveal that the Mg-8 Zn-1 Ag-0.7 Zr alloy is solidified in form of equiaxial crystal

and the as-cast alloy is mainly composed of the α-Mg、Mg-Zn-Ag ternary compound and Zn

2

Zr

3

phase. The second phase is mainly distributed along the grain boundary. After heat treatment

distribution morphology of secondary phase is improved obviously on the grain boundary. Zn content in the matrix is changed greatly. After solid solution

Zn content in the alloy is increased from 3.09% in as-cast state to 8.24%

while it is decreased to 5.42% after aging treatment

presenting the satisfied precipitate strengthening effects. The tensile strength

yield strength and elongation of the alloy by T4 treatment reach 311.4 MPa

147.4 MPa and 13.7%. After T6 treatment

the tensile strength

yield strength and elongation of the alloy reach 325.4 MPa

217.6 MPa and 5.1%

respectively.