热处理对双相Mg-8Li-4Al-3Zn-La合金组织与性能的影响

分别对原始态的双相Mg-8Li-4Al-3Zn-La合金进行固溶及退火处理,通过光学显微镜、扫描电镜以及X射线衍射等方法研究合金在不同热处理状态下微观组织的变化,测定了合金硬度及拉伸性能并分析了断口。研究结果表明,经固溶处理后合金抗拉强度明显提高,由原来的194MPa提升到243MPa,延伸率由18%降至9%;而退火处理后其强度没有提升,塑性反而下降。此外,合金中两相组织与第二相分布具有明显差异,使得各相性能及其对热处理的反应不同。

Effects of Thermal Treatment on the Microstructures and Mechanical Properties of Mg-8Li-4Al-3Zn-La Alloy

The dual-phase alloy Mg-8Li-4Al-3Zn-La was subject to homogenization and aging treatments.The microstructures and phase were characterized by optical microscope,scanning electron microscope (SEM) and X-ray diffraction (XRD).The hardness and tensile properties as well as fracture characteristics of the alloys were also measured and analyzed.The results show that the tensile strength is increased from 194 MPa to 243 MPa after solid solution treatment,and the elongation to failure decreases from 18％ to 9％.After aging,the tensile strength changes slightly,but the elongation to failure decreases greatly.Moreover,the mechanical properties of individual phase have distinct differences due to the different distribution of second phases in the alloy.