Based on ZK60alloy

ZYK820and ZYK610alloys with different mass ratio of Zn/Y such as8∶2

6∶1have been prepared by semi-continuous casting.The microstructure and mechanical properties of two alloys prepared were investigated by optical microscopy

SEM

XRD and EDS.The effects of Zn/Y mass ratio on the fracture mechanism of ZK60alloy were observed by SEM.The results reveal that the addition of Y has a little effect on the grain size of ZK60alloy

however

grain boundary morphology can be changed obviously.When the mass ratio of Zn/Y is 8∶2

the second phase in the ZYK820alloy is mainly W-Mg

3

Zn

3

Y

2

phase with a trace amount of I-Mg

3

Zn

6

Y phase and X-Mg

12

ZnY phase

while with Zn/Y mass ratio of 6∶1

the second phase is mainly I-Mg

3

Zn

6

Y

which are formed at the triangle in form of the fishbone or parallelogram-shaped

while the grain boundaries are extended into the crystal with reticular distribution.When the mass ratio of Zn/Y is 6∶1

tensile strength

yield strength and elongation of the alloy are improved by 4.4%

7.6%and 4%

respectively.In addition

the fracture mechanism is characterized by brittle fracture mixed with a certain toughness fracture.