La对Al-5Mg-0.2Zr合金组织和性能的影响

Effect of La Elements on Microstructure and Mechanical Properties of Al-5Mg-0.2Zr Alloy

采用铸锭冶金法制备了含稀土La的Al-Mg-Zr合金,通过金相显微镜、扫描电镜、能谱和X射线衍射及力学性能测试,观察分析了0.2%的La微合金化对Al-5Mg-0.2Zr合金微观组织和力学性能的影响。结果表明,在Al-5Mg-0.2Zr合金中添加0.2%的La能显著细化合金晶粒,合金的平均晶粒尺寸下降到68μm,同时有效地避免了Al3Zr析出相的粗化和偏聚,使合金抗拉强度、屈服强度及伸长率分别增加到了165.5MPa、112.5MPa和7.5%。

Al-Mg-Zr alloys containing La elements were prepared by cast metallurgy. Effects of 0.2 % La additions on mierostructure and mechanical properties of Al-5Mg-0.2Zr alloy were investigated by tensile testing, optical microscopy （OM）, scanning electron microscopy （SEM）, energy spectrum （EDS） and X-ray diffraction （XRD）. The results show that the addition of 0.2% La can positively refine the grain size of Al-5Mg-0.2Zr alloy and effectively avoid the coarsening and segregation of AI3Zr in the matrix, and the average grain size of the alloy is decreased to only 68μm. Meanwhile, the tensile strength, yield strength and elongation are increased to 165.5 MPa,112.5 MPa and 7.5%, respectively.