The purpose of this paper is to study large-sized copper billets refined with 5N ultrahigh purity after vacuum melting and directional solidifi-cation （VMDS）. The precise impurity analysis of copper billets was carr...The purpose of this paper is to study large-sized copper billets refined with 5N ultrahigh purity after vacuum melting and directional solidifi-cation （VMDS）. The precise impurity analysis of copper billets was carried out with a glow discharge mass spectrometer （GDMS）. The re-sults demonstrate that the total concentration of twenty-two impurities is decreased by 63.1wt.%-66.5 wt.%. Ag, P, S, Na, Mg, Se, Zn, In and Bi are easy to be removed due to lgPimp - lgPCu 1.5, and they can be removed effectively under the vacuum condition of 1650-1700 K for 30 min. The electrical conductivity of 5N copper is higher than that of the raw material as the impurity concentrations decrease. The segrega-tion effect in directional solidification can be remarkable when the equilibrium distribution coefficient （k0） value is less than 0.65 due to the strong affinity of Cu for some metallic and non-metallic impurities.展开更多
The metal oxide dissolved in pure copper is usually cuprous oxide （Cu<sub>2</sub>O）, so thedeoxidization of pure copper means the reduction of cuprous oxide to copper by addingdeoxidizers such as an elem...The metal oxide dissolved in pure copper is usually cuprous oxide （Cu<sub>2</sub>O）, so thedeoxidization of pure copper means the reduction of cuprous oxide to copper by addingdeoxidizers such as an element. It is required that the oxide of this element must be morestable than Cu<sub>2</sub>O, i.e. its decomposition pressure is less than that of Cu<sub>2</sub>O. The more展开更多
Electrical conductance and temperature of electric copper busbar joints were measured under different torque moments. Experimental results show that laser surface melting can increase hardness and refine structure of ...Electrical conductance and temperature of electric copper busbar joints were measured under different torque moments. Experimental results show that laser surface melting can increase hardness and refine structure of the copper, and it does not deteriorate electric resistance. Meanwhile, the temperature of laser treated joints under electric current is slightly lower than that of original sample. Salt spray test shows that laser treated sample has better salt spray corrosion resistance than the original sample does. The electric resistance of both laser treated and original samples are increased with salt spray time. For the same salt spray time, the electric resistance of busbar joint is decreased with increasing torque moment.展开更多
In the paper, a melt extraction method was used to fabricate Cu–4Ni–14Al（wt%） fiber materials with diameters between 50 and 200 μm. The fibers exhibited superelasticity and temperature-induced martensitic transfo...In the paper, a melt extraction method was used to fabricate Cu–4Ni–14Al（wt%） fiber materials with diameters between 50 and 200 μm. The fibers exhibited superelasticity and temperature-induced martensitic transformation. The microstructures and superelasticity behavior of the fibers were studied via scanning electron microscopy（SEM） and a dynamic mechanical analyzer（DMA）, respectively. Appropriate heat treatment further improves the plasticity of Cu-based alloys. The serration behavior observed during the loading process is due to the multiple martensite phase transformation.展开更多
文摘The purpose of this paper is to study large-sized copper billets refined with 5N ultrahigh purity after vacuum melting and directional solidifi-cation （VMDS）. The precise impurity analysis of copper billets was carried out with a glow discharge mass spectrometer （GDMS）. The re-sults demonstrate that the total concentration of twenty-two impurities is decreased by 63.1wt.%-66.5 wt.%. Ag, P, S, Na, Mg, Se, Zn, In and Bi are easy to be removed due to lgPimp - lgPCu 1.5, and they can be removed effectively under the vacuum condition of 1650-1700 K for 30 min. The electrical conductivity of 5N copper is higher than that of the raw material as the impurity concentrations decrease. The segrega-tion effect in directional solidification can be remarkable when the equilibrium distribution coefficient （k0） value is less than 0.65 due to the strong affinity of Cu for some metallic and non-metallic impurities.
文摘The metal oxide dissolved in pure copper is usually cuprous oxide （Cu<sub>2</sub>O）, so thedeoxidization of pure copper means the reduction of cuprous oxide to copper by addingdeoxidizers such as an element. It is required that the oxide of this element must be morestable than Cu<sub>2</sub>O, i.e. its decomposition pressure is less than that of Cu<sub>2</sub>O. The more
文摘Electrical conductance and temperature of electric copper busbar joints were measured under different torque moments. Experimental results show that laser surface melting can increase hardness and refine structure of the copper, and it does not deteriorate electric resistance. Meanwhile, the temperature of laser treated joints under electric current is slightly lower than that of original sample. Salt spray test shows that laser treated sample has better salt spray corrosion resistance than the original sample does. The electric resistance of both laser treated and original samples are increased with salt spray time. For the same salt spray time, the electric resistance of busbar joint is decreased with increasing torque moment.
基金financial support of the National High Technology Research and Development Program of China (No. 2009AA03Z113)the National Science Foundation of China (No. 51471025)
文摘In the paper, a melt extraction method was used to fabricate Cu–4Ni–14Al（wt%） fiber materials with diameters between 50 and 200 μm. The fibers exhibited superelasticity and temperature-induced martensitic transformation. The microstructures and superelasticity behavior of the fibers were studied via scanning electron microscopy（SEM） and a dynamic mechanical analyzer（DMA）, respectively. Appropriate heat treatment further improves the plasticity of Cu-based alloys. The serration behavior observed during the loading process is due to the multiple martensite phase transformation.
