Microstructure and Mechanical Properties of Mg-2.5Zn-1.0Ca-xSn Alloys

The microstructure and mechanical properties of as-cast Mg-2.5Zn-1.0Ca-xSn（x=0.1-2.0） alloy were studied by OM,SEM,XRD,hardness test and tensile test.The results show that the microstructure of Mg-2.5Zn-1.0Ca-xSn alloy is mainly composed of α-Mg,Mg₂Ca,Ca₂Mg₆Zn₃and Mg₂Sn phases.With the increase of Sn content,the average grain size of the alloy decreases gradually,the amount of Mg₂Sn phase at the grain boundary increases gradually,and the size increases continuously.With the increase of Sn content,the hardness of the alloy increases gradually,and the tensile strength and elongation of the alloy increase first and then decrease.The tensile strength and elongation of Mg-2.5Zn-1.0Ca-1.0Sn alloy are highest,which are 145.3 MPa and 4.6%,respectively.