Mg-5Al-1Sr-2Ca-xY合金组织及力学性能

Microstructure and mechanical properties of Mg-5Al-1Sr-2Ca-xY alloys

制备了不同Y含量的Mg-5Al-1Sr-2Ca-xY(x=0,1,2,5)合金试样,采用光学显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射仪(XRD)、材料试验机等观察测试合金的微观组织和力学性能。结果表明,未添加Y时,合金晶粒大小不均匀,且多呈柱状,晶内有较多的点状化合物;Y含量1%时,晶粒细化、球化且大小较均匀;Y含量2%时,晶粒趋于柱状;Y含量5%时,晶粒形状不规则、大小极不均匀。随Y含量的增加,室温和高温力学性能呈先升后降趋势,最高点为Y含量1%,其室温和高温抗拉强度分别较无Y合金提高了约33.8%和25.4%。

Mg-5Al-lSr-2Ca-xY （x = 0 -5 ）magnesium alloys were melted in a grabhite crucible furnace under argon atmosphere. Microstructure and mechanical properties of the alloys were examined by means of metallographic microscope, SEM, XRD and tensile tests. The results show that when Y addition is 1% , the grain size is refined and more uniform with spheroidal shape, while without Y addition, the alloys present irregular columnar grains with spotshaped compounds. When Y addition is 2 % , the alloy presents fine columnar grains, and the nonuniform and irregular grains are observed in the alloy with addition of 5% yttrium. When the Y addition is 1% , tensile strength of the alloy at ambient and elevated temperature is improved by 33.8% and 25.4% compared with that of the alloy without Y addition, however, with the Y addition of 2% -5 % , the tensile properties of the alloys decrease obviously.