Mg

99.9-3x

Zn

x

Y

2x

Zr

0.1

（x=0.5

1

2

molar fraction

%）alloys reinforced with LPSO structure was prepared by rheo-squeeze casting.Microstructure and mechanical properties of the alloys prepared were investiagted.The results reveal that rheo-squeeze casting can refine effectively the microstructure of the alloys.The matrix structures of the alloys are composed of largerα1-Mg and smallerα2-Mg grains.The LPSO structure is distributed uniformly in the grain boundary.The lower the content of LPSO structure is

the more obvious the refining effect is.With the increase of squeeze pressure

the thickness of LPSO structure in the alloys is decreased.After the squeeze pressure reaches 100 MPa

the thickness is changed slowly with increasing in pressure.Compared with conventional gravity casting

rheo-squeeze casting can improve effectively the mechanical properties of the alloys

especially for the elongation

where the tensile strength and elongation of the rheo-squeeze casting Mg

96.9

Zn

1

Y

2

Zr

0.1

alloy under 400 MPa are improve by 19%and 170%

respectively.