【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（质量分数,%）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α-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%。更多还原

【Abstract】 The microstructure and mechanical properties of as-cast, solution-treated and as-extruded Mg-8 Li-4 Al-0.3 Y alloys were studied by optical microscope（OM）, scanning electron microscope（SEM）, X-ray diffraction analysis（XRD） and tensile test machines. The results show that as-cast Mg-8 Li-4 Al-0.3 Y alloy is composed of ɑ-Mg, β-Li, Al₂Y, Al Li and Mg AlLi₂ phases. Mg AlLi₂ compound at the grain boundaries disappears in the solution-treated alloy and most of AlLi phase decompose and dissolve into the matrix, while only part of larger AlLi particles are left during the solution treatment. The microstructure of the as-extruded alloy is refined obviously and more uniform due to the dynamic recrystallization during the extrusion process. The microhardness of the solution-treated alloy is much higher than that of as-cast one due to solution strengthening. The mechanical properties of Mg-8 Li-4 Al-0.3 Y alloys are improved a lot by extrusion and the ultimate strength and elongation of the extrude alloy reach 208 MPa and 25.1%, respectively.更多还原