【摘要】 为了提高合金的力学性能，通过微合金化的方法设计了一种新型超轻Mg-3.0Li-2.0Al-2.0Sn-1.0Y-0.5Er合金，通过熔铸、均匀化、多向锻造和异步轧制工艺获得了细晶镁合金板材。采用光学显微镜、X射线衍射仪、扫描电子显微镜、能谱仪等表征手段研究了合金微观组织的演变，利用拉伸试验机测试了合金变形前后的室温拉伸性能，研究了不同状态下合金的力学性能，讨论了合金力学性能与微观组织转变的影响因素。结果表明，在铸态Mg-3.0Li-2.0Al-2.0Sn-1.0Y-0.5Er合金中存在着α-Mg基体和Mg2Sn、AlLi、Al2Y和Al2Er等第二相颗粒，多向锻造和异步轧制组合工艺有效地细化了Mg-3.0Li-2.0Al-2.0Sn-1.0Y-0.5Er合金的晶粒，使合金的平均晶粒尺寸减小到7.15μm，室温下的抗拉强度、屈服强度和伸长率分别提高至255 MPa、220 MPa和24.9%。更多还原

【Abstract】 To improve the mechanical properties of the alloy, a new ultralight Mg-3.0Li-2.0Al-2.0Sn-1.0Y-0.5Er alloy was designed by micro-alloying. Fine grained Mg alloy plates were obtained by melting casting, homogenization, multi-directional forging and differential speed rolling. The microstructural evolution of the alloy was studied by means of optical microscope, X-ray diffraction,scanning electron microscope and energy dispersive spectroscopy. The room-temperature tensile properties of the alloy before and after deformation were tested by tensile testing machine. The mechanical properties of the alloy under different conditions were studied. The influencing factors of the mechanical properties and microstructure transformation of the alloy were discussed. The results showed that α-Mg matrix and second phase particles such as Mg2Sn, AlLi, Al2Y and Al2Er exist in the as-cast Mg-3.0Li-2.0Al-2.0Sn-1.0Y-0.5Er alloy. The combined process of multi-directional forging and differential speed rolling effectively refines the grains of Mg-3.0Li-2.0Al-2.0Sn-1.0Y-0.5Er alloy,reduces the average grain size of the alloy to 7.15 μm, and increases the ultimate tensile strength, yield strength and elongation at room temperature to 255 MPa, 220 MPa and 24.9%, respectively.更多还原