Effects of rare earth Ce addition on microstructure and mechanical properties of impure copper containing Pb
(1. College of Nuclear Equipment and Nuclear Engineering, Yantai University, Yantai 264005, China;
2. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China;
3. College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, China)
2. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China;
3. College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, China)
Abstract: The effects of rare earth Ce on the microstructure and mechanical properties of impure copper containing Pb were investigated using OM, SEM, EPMA, TEM and tensile testing. TEM and EDS analysis reveal that spherical CePb3 particles form after Ce addition. CePb3 particles, with average size of ~3.6 μm, homogenously distribute in the Cu matrix. Due to small lattice misfit (~4.62%) with Cu matrix, CePb3 particles can act as effective nucleation sites beneficial to the grain refinement. Pb at grain boundaries seriously deteriorates the mechanical properties of Cu. The tensile strength and the elongation of Cu-0.1Pb are decreased by 43.1% and 56.7% compared with those of pure copper, respectively. Ce can purify grain boundaries, cause the precipitation of CePb3 particles and refine grain sizes, which contribute to significant improvement of the mechanical properties of Cu. Compared with Cu-0.1Pb, the tensile strength (179 MPa) and the elongation (38.5%) of Cu-0.1Pb-0.3Ce are increased by 117.6% and 151.6%, respectively.
Key words: Ce addition; impure copper containing Pb; CePb3 second phase particle; lattice misfit; grain refinement; mechanical property