Ce、Y 和Gd对Mg-3Sn-2Sr镁合金铸态组织和力学性能的影响

摘要

通过扫描电镜、X射线衍射、差热分析以及抗拉和蠕变性能测试等手段，调查和比较了Ce、Y 和Gd对Mg-3Sn-2Sr 镁合金铸态组织和力学性能的影响。结果表明：Mg-3Sn-2Sr 三元合金主要由α-Mg、初生和共晶SrMgSn 以及 Mg2Sn 相组成。当添加1.0%Ce、1.0%Y 和1.0%Gd 到 Mg-3Sn-2Sr 合金后，合金中分别形成了Mg12Ce、YMgSn、GdMgSn 和/或 Mg17Sr2相。同时，合金中初生 SrMgSn 相的形成被抑制，且呈针状的粗大初生SrMgSn相也被变质和细化。此外，添加1.0%Ce、1.0%Y 和1.0%Gd均能同时改善Mg-3Sn-2Sr合金的抗拉性能和蠕变性能。在含Ce、Y 和Gd合金中，含Ce合金的抗拉性能相对较含Y 和含Gd合金的高。%The effects of Ce, Y and Gd additions on the as-cast microstructure and mechanical properties of Mg-3Sn-2Sr alloy were investigated and compared by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry analysis, tensile and creep tests. The results indicate that the Mg-3Sn-2Sr ternary alloy is mainly composed ofα-Mg, primary and eutectic SrMgSn, and Mg2Sn phases. After the additions of 1.0%Ce, 1.0%Y and 1.0%Gd to the Mg-3Sn-2Sr alloy, the Mg12Ce, YMgSn, GdMgSn and/or Mg17Sr2 phases are formed, respectively. At the same time, the formation of the primary SrMgSn phase is suppressed and the coarse needle-like primary SrMgSn phase is modified and refined. In addition, the additions of 1.0% Ce, 1.0% Y and 1.0% Gd to the Mg-3Sn-2Sr alloy can simultaneously improve the tensile and creep properties of the alloy. Among the Ce-, Y-and Gd-containing alloys, the tensile properties of the Ce-containing alloy are relatively higher than those of the Y-and Gd-containing alloys.