稀土Er对Al-5.3Cu-0.8Mg-0.6Ag合金组织与性能的影响

Effect of rare earth erbium on microstructure and mechanical properties of Al-5.3Cu-0.8Mg-0.6Ag alloy

采用硬度测试、拉伸性能测试、X射线衍射、金相观察、扫描电镜与透射电镜等方法,研究了添加0.2wt%Er对Al-5.3Cu-0.8Mg-0.6Ag合金的组织与性能影响。结果表明,微量稀土Er可显著降低铸态合金的晶粒尺寸,提高铸态合金的室温与高温力学性能;然而,Er降低了挤压态合金的时效硬化与拉伸性能,这是由于Er与合金中的Al、Cu形成了Al8Cu4Er稀土化合物,减少了用于固溶时效的Cu元素,最终使强化析出相Ω相的体积分数减少。

The microstructure and mechanical properties of Al5.3Cu-0.8Mg-0.6Ag alloy with or without addition of erbium were investigated by means of hardness measurement,tensile testing,optical microscope,XRD, SEM and TEM.The results show that erbium addition refines grain size and improves mechanical properties of the as-cast alloys at room temperature and high temperature.However,the erbium addition decreases the amount of Ω phase after peak aging,and thus decreases hardness and tensile properties of the extruded alloy,which is caused by the formation of Al8Cu4Er compound.