The microstructure of rolled Mg-Y-Ce-Sn-Zr alloy was obserevd by means of optical microscope（OM）

X-ray diffractometer（XRD）and scanning electron microscopy（SEM）.The effects of Sn on the properties of the alloy prepared were investigated by tensile and hardness test.The results show that with the increase of Sn content

the average grain size in the alloy is decreased firstly and then increased.When the Sn content is 1.5%

the grain refinement effect presents desirable

where grain size is about 12.5μm.The MgYSn phase is increased with the increase of Sn content

and the second phase nucleation（PSN mechanism）promotes recrystallization and changes the crystal orientation

so that the texture strength of the（0002）basal plane is gradually weakened with the increase of Sn

and the alloy plasticity is improved.When Sn content is 1.5%

the comprehensive properties of the alloy are satisfactory

where yield strength

tensile strength

elongation and micro-hardness reach 153 MPa

223 MPa

19.5%and 68.9 HV

respectively.