The influence of squeeze casting on the microstructure

casting defects and mechanical properties of Mg-14Zn-3Al was investigated by OM

XRD and SEM.The results show that the microstructure of as-squeezed Mg-14Zn-3Al alloy is composed ofα-Mg matrix

long blockτ-Mg32（Al

Zn）49 phase and granular or skeleton-likeε-MgZn phase.With the increase of the squeeze pressure

the microstructure of the alloy is refined and the quantity of the second phase is increased.Meanwhile

the casting defects in the alloy are inhibited

whose area fraction in the casting is sharply reduced from 15.67% to 0.81%.After squeeze casting treatment

the tensile strength and elongation of Mg-14Zn-3Al alloy can reach 218.1 MPa and 5.2%

respectively

which are much higher than those of gravity casting（192.6 MPa

1.2%）.