Mg-8Li-4Al-0.3Y合金微观组织与力学性能研究

Research on Microstructure and Mechanical Properties of Mg-8Li-4Al-0.3Y Alloys

摘要:

利用光学显微镜(OM)、扫描电子显微镜(SEM)和X射线衍射仪(XRD)等手段系统研究了铸态、固溶处理态和挤压态Mg-8Li-4Al-0.3Y合金的微观组织，测试了其室温力学性能。实验结果表明：铸态实验合金主要由ɑ-Mg、β-Li、Al2Y和AlLi相以及MgAlLi2相组成；固溶处理后合金中在相界处分布的MgAlLi2化合物相消失，大量AlLi相发生分解并固溶于合金基体中，仅剩下部分尺寸较大的AlLi相。在挤压过程中合金发生动态再结晶，显微组织明显细化，组织更加均匀。固溶处理后合金基体硬度明显高于铸态合金；与铸态相比，挤压态合金的综合力学性能得到大幅提升，其抗拉强度和延伸率分别达到208 MPa和25.1%。

Abstract:

The microstructure and mechanical properties of as-cast, solution-treated and as-extruded Mg-8Li-4Al-0.3Y alloys were studied by optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction analysis (XRD) and tensile tests machines, etc. The results show that as-cast Mg-8Li-4Al-0.3Y alloys are composed of ɑ-Mg, β-Li, Al2Y, AlLi and MgAlLi2 phases. MgAlLi2 compound and most of AlLi phase decomposes and dissolves into the matrix, only part of larger AlLi particles are left during the solution treatment. The micro-hardness of solution-treated alloy is much higher than that of as-cast one due to solution strengthening. The mechanical properties of Mg-8Li-4Al-0.3Y alloys are improved a lot by extrusion and the ultimate strength and elongation of the extrude alloy reaches to 208 MPa and 25.1% respectively.