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在Al-4.5Cu铸造铝合金中添加微量的富铈混合稀土,用光学显微镜、扫描电镜以及能谱分析等手段研究稀土元素对合金组织、力学性能和断裂特性的影响。结果表明,稀土可以显著细化α-Al枝晶并减小二次枝晶间距;与此同时,枝晶间区域形成了骨骼状或块状稀土化合物相,Al2Cu和稀土化合物相相互交织在一起呈网状分布。添加富铈混合稀土后,合金的屈服强度略微降低,抗拉强度增加。添加富铈混合稀土改善了合金的塑性,合金延伸率增加至7.4%～8.84%,其断裂机制由脆性断裂转变为韧性断裂。
The effects of rare earth elements on the microstructure, mechanical properties and fracture properties of Al-4.5Cu aluminum alloy were studied by optical microscopy, scanning electron microscopy and energy spectrum analysis. The results show that rare earth can significantly refine the α-Al dendrite and reduce the secondary dendrite spacing; at the same time, the intergranular intergranular formed skeletal or massive rare earth compound phase, Al2Cu and rare earth compound phase intertwined Mesh distribution. Adding cerium-rich mixed rare earth, the yield strength of the alloy slightly reduced, the tensile strength increases. The addition of cerium-rich mixed rare earth improves the plasticity of the alloy, and the alloy elongation increases to 7.4% ~ 8.84%. The fracture mechanism changes from brittle fracture to ductile fracture.