Zr和固溶冷却方式对Mg-Er-Zn合金组织和性能的影响

Effect of Zr and Solid Solution Cooling Ways on Microstructures and Mechanical Properties of Mg-Er-Zn Alloys

利用光学显微镜、扫描电镜、能谱分析仪、X射线衍射仪及压缩试验等,研究了Zr和固溶工艺对Mg-Er-Zn合金组织和力学性能的影响。结果表明,Zr的加入不影响合金的相组成,但晶界处X相的质量分数减少。Zr显著细化了Mg97.5Er2Zn0.5合金的组织,提高了合金力学性能。Zr的加入缩短了X相完全固溶的时间;合金在固溶后采用炉冷工艺时晶内析出条纹状LPSO相,而在水冷时没有发现。固溶后,合金力学性能高于铸态合金,加Zr后合金的力学性能高于无Zr合金,炉冷合金的力学性能低于水冷合金。

Effects of Zr and solid solution treatment on microstructure and mechanical properties of Mg- Er-Zn alloys were investigated by OM （optical microscopy）, SEM （scanning electron microscopy）, EDS （energy dispersed spectrometer）, XRD （X-ray diffraction） and compressive testing. The results reveal that the phase structure change is absent with Zr addition, however, the percentage composition of X phase in grain boundary is decreased. The microstructure and mechanical properties of Mg97.5 Er2 Zn0.5 al- loy are improved significantly with Zr addition. Meanwhile, the solution time of X phase is reduced. The LPSO phase can be observed in the furnace cooled alloys after solid solution treatment, while it is absent in the water cooled alloy. After solid solution treatment, the mechanical properties of the solu- tion-treated alloys are higher than those of the as-cast alloys, and the Mg97.32 ErzZn0.5 Zr0.18 alloy is the higher than Mg97.5 Er2 Zn0.5 alloys in mechanical properties. In addition, the mechanical properties of fur- nace cooled alloys are higher than those of the water cooled alloys.