The microstructure and mechanical properties of as cast Mg Sn binary alloys were studied by optical microscopy, scanning electron microscopy (SEM), Energy Dispersive X-ray (EDX) Analysis, X-ray diffraction (XRD) quantitative and qualitative analysis, tensile strength and micro-hardness testing. The results showed that Mg-Sn binary alloy is composed of α-Mg matrix and Mg2Sn. The mechanical tests indicated that the micro-hardness of the alloy increases when Sn content raises, the main reason of which was the dispersion strengthening of Mg2Sn and the grain refinement strengthening of Sn. The tensile strength and elongation of the alloys grow with the increase of Sn content when the content of Sn≤5%(wt). The grain refinement of Sn acts as the leading role in this content range of Sn. The tensile strength and especially elongation decline for Mg-10%Sn alloy, which owes mainly to the disappearance of grain refinement strengthening and the increase of brittle Mg2Sn phase.
