Effects of heat treatment on microstructure and mechanical properties of Mg-3Sn-1Mn magnesium alloy

The effects of heat treatment on the microstructure and mechanical properties of Mg-3Sn-1Mn alloy were preliminarily investigated by using optical and electron microscopy, X-ray diffraction (XRD) analysis, and tensile and creep test. The results indicate that the heat treatment has an obvious effect on the microstructure and mechanical properties of the Mg-3Sn-1Mn alloy. After the solid solution treatment at 420 °C, a majority of the Mg2Sn phases in the alloy are dissolved into the matrix. However, after the further aging treatment at 250 °C, lots of fine Mg2Sn phases in the aged alloy are precipitated at the grain boundaries and within the grains. As a result, the tensile and creep properties of the aged alloy are significantly improved. The mechanism for the higher tensile and creep properties of the aged alloy is related to the dispersive distribution of the Mg2Sn phase in the α-Mg matrix.