(北京科技大學(xué) 材料科與工程學(xué)院，北京 100083)
摘 要: 采用真空感應(yīng)熔煉技術(shù)得到Cu-0.4Cr-0.2Zr-0.15Mg-RE鑄錠，通過金相顯微鏡觀察加入不同含量稀土的金相組織，采用SEM觀察組織形貌并對合金組織進行EDXS能譜分析，最后測試銅合金的力學(xué)性能和導(dǎo)電性能。結(jié)果表明:加入La和Ce后，合金晶粒細化，組織均勻致密，Cr、Mg析出相在基體中的分布由條狀、帶狀轉(zhuǎn)變?yōu)辄c狀、細塊狀。稀土元素主要分布在晶界處，加入稀土元素后，合金的抗拉強度有大幅度的提高，分別加入0.10%的La和0.10%的Ce后，合金的峰值強度分別為250.13 MPa和259.32 MPa，相比于不加稀土的212.34 MPa，分別提高了17.80%、22.13%;加入0.15%稀土元素La和Ce后，合金的導(dǎo)電率則隨著稀土元素含量的增加呈單調(diào)增加，且La對銅合金導(dǎo)電性能的提高作用優(yōu)于Ce的，但兩者相差微小。因此，從提高合金綜合性能方面考慮，加入0.10%的Ce是最佳選擇。
關(guān)鍵字: Cu-0.4Cr-0.2Zr-0.15Mg-RE;顯微組織;元素分布;稀土;La;Ce;力學(xué)性能
（School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:Under the vacuum condition, the Cu-0.4Cr-0.2Zr-0.15Mg-RE ingot was gotten by using the method of induction heating and vertical centrifugal casting. By metallurgical microscopy, the microstructures of containing 0.05%, 0.10%, 0.15%La and Ce were analyzed. The microstructure 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 microstructures of the alloy adding Ce and La are uniform 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% La and 0.1%Ce, the peak strength are 250.13 MPa and 259.32 MPa, respectively, increasing by 17.8% and 22.13% compared the 212.34 MPa without rare 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.
Key words: Cu-0.4Cr-0.2Zr-0.15Mg-RE; microstructure; elements distribution; rare earth; La; Ce; mechanical property
