The effects of Zn addition on the as-cast microstructure and tensile properties of Mg-10Gd-2Y-0.5Zr magnesium alloy were investigated.The results show that the as-cast structure of Mg-10Gd-2Y-0.5Zr magnesium alloy is mainly composed ofα-Mg

Mg

5

（Gd

Y）and Mg

24

（Y

Gd）

5

phase

and after adding 0.5%～1.5%Zn

the as-cast structure of the measured alloy is mainly composed ofα-Mg

Mg

5

（Gd

Y

Zn）

Mg

24

（Y

Gd

Zn）

5

and Mg

12

（Gd

Y）Zn phase.In addition

the addition of Zn also has a obvious effect on the as-cast ambient tensile properties of the Mg-10Gd-2Y-0.5Zr magnesium alloys.After adding 0.5%Zn

the ambient tensile properties of the measured magnesium alloys are significantly increased.After adding 1.0%and 1.5%Zn

the ambient tensile properties of the alloys are gradually decreased.The magnesium alloy with 0.5%Zn has the satisfied comprehensive mechanical properties

and its tensile strength

yield strength and elongation reach up to 197MPa

160MPa and 4.37%

respectively.The influence of Zn content on the as-cast tensile properties of Mg-10Gd-2Y-0.5Zr alloys may be related with the formation and quantity of the second phase of Mg

5

（Gd

Y

Zn）

Mg

24

（Y

Gd

Zn）

5

and Mg

12

（Gd

Y）Zn in the as-cast structure of Zn-containing magnesium alloys.