稀土元素La、Ce含量对Cu-0.4Cr-0.2Zr-0.15Mg合金组织和性能的影响

摘要

采用真空感应熔炼技术得到Cu-0.4Cr-0.2Zr-0.15Mg-RE铸锭，通过金相显微镜观察加入不同含量稀土的金相组织，采用SEM观察组织形貌并对合金组织进行EDXS能谱分析，最后测试铜合金的力学性能和导电性能。结果表明：加入La和Ce后，合金晶粒细化，组织均匀致密，Cr、Mg析出相在基体中的分布由条状、带状转变为点状、细块状。稀土元素主要分布在晶界处，加入稀土元素后，合金的抗拉强度有大幅度的提高，分别加入0.10%的La和0.10%的Ce后，合金的峰值强度分别为250.13 MPa和259.32 MPa，相比于不加稀土的212.34 MPa，分别提高了17.80%、22.13%；加入0.15%稀土元素La和Ce后，合金的导电率则随着稀土元素含量的增加呈单调增加，且La对铜合金导电性能的提高作用优于Ce的，但两者相差微小。因此，从提高合金综合性能方面考虑，加入0.10%的Ce是最佳选择。%Under the vacuum condition, the Cu-0.4Cr-0.2Zr-0.15Mg-RE ingot wasgottenby using the method of induction heating and vertical centrifugal casting.Bymetallurgical microscopy, the microstructures of containing 0.05%, 0.10%,0.15%La and Ce were analyzed.Themicrostructure of Cu-0.4Cr-0.2Zr-0.15Mg-RE alloy as-casting was examined by SEM and EDXS. The mechanical and electrical properties of copper alloys were also tested. The results show that the microstructuresof the alloy adding Ce and Laareuniform and compact, and the distributions of Cr,Mg precipitates in the matrix change from strip to the point,fine homogeneous,while the rare earth elements are mainly located in the grain boundaries. With the additions of the rare earth elements, the tensile strengths of the alloy improve greatly. When containing 0.1% Laand0.1%Ce,thepeak strengthare250.13MPaand259.32MPa,respectively, increasing by 17.8%and22.13% compared the 212.34MPawithoutrare earth elements. In the range of 0.15%, the electric conductivity of the alloy increases with the increase of the contents of the rare earth elements. And the effect of La on the improvement of the electric conductivity is better than that of Ce although the gap is small.Therefore, considering the effect of improving comprehensive properties of alloy,adding 0.1%Ce is the best choice.