【摘要】 紫杂铜中多种微量杂质元素并存,其中的杂质元素会恶化铜材的加工性能和物理力学性能,进而缩短铜材的使用寿命。稀土元素在紫杂铜中可以起到除杂、微合金化、细化组织、改善力学性能和耐蚀性能等多种作用。分别从稀土元素镧、铈在铜中除杂的热力学原理、除杂顺序、稀土相的存在形式、微合金化机制、稀土诱导铜微观组织转变的判据及工业化应用等方面进行了研究和阐述。结果表明,稀土的净化作用、晶粒细化及第二相强化作用可以改善紫杂铜的力学性能和耐蚀性能,稀土Ce除杂的热力学顺序为:O>S>Bi>Sn>Pb>Si>Al>Ag>Fe。稀土微合金化可以使铜的凝固组织发生柱状晶向等轴晶的转变(CET),稀土的净化效应和成分过冷共同作用导致了纯铜中CET的转变,建立了基于稀土含量为判据的CET预测模型,并确定了铜凝固组织发生CET转变的临界稀土La含量为0.14%。未来,紫杂铜的稀土除杂直接再利用技术有望得到实际工业应用。更多还原

【Abstract】 Many kinds of impurity elements exist in impure red-copper,which would deteriorate the processability,the physical and mechanical properties and shorten the service life of copper products. Rare earth( RE) elements addition can remove impurities,microalloy,refine microstructure,improve mechanical properties and corrosion resistance properties. In this paper,the thermodynamic mechanisms and rules of RE removing impurities,the existence forms of RE phases,the mechanisms of microalloying,the microstructure transition induced by RE and the application of RE in industrial production were explored and discussed in details. Results showed that RE refining improved the mechanical properties and the corrosion resistance properties of impure red-coppers for the purification effect,the grain refining and the second phase strengthening effect. The thermodynamic order of Ce removing impurities was O > S > Bi> Sn > Pb > Si > Al > Ag > Fe. RE alloying resulted in a columnar to equiaxed transition( CET) for the effects of purification and constitutional undercooling. A new prediction model for CET based on the RE content was established and the critical composition of CET of pure copper with RE La microalloying was 0. 14%. Considering the above research results,the direct reuse technology of impure red-copper by removing impurities with RE elements would gain industrial application in near future.更多还原