The vacuum medium-frequency induction melting technology was employed to prepare the Cu-15%Cr-0.24%Zr alloy. The scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, transmission electron micr...The vacuum medium-frequency induction melting technology was employed to prepare the Cu-15%Cr-0.24%Zr alloy. The scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, transmission electron microscopy （TEM） and high-resolution transmission electron microscopy （HRTEM） were used to analyze the phase composition, morphology and structure of the alloy. The results reveal that the as-cast structure of the alloy consists of Cu matrix, Cr dendrite, eutectic Cr and Zr-rich phase. A large number of Cr-precipitated phases occur in the Cu matrix, and Cu5Zr particles can be found in the grain boundary of Cu matrix. The HRTEM images prove that there is a semi-coherent relationship between Cu5Zr and Cu matrix.展开更多
The Cu-15Cr in-situ fiber-reinforced composites sheets were prepared by cold drawing combined with cold rolling process. The evolution process of Cr fibers was studied, and when cold rolling reduction ε = 95%, the mo...The Cu-15Cr in-situ fiber-reinforced composites sheets were prepared by cold drawing combined with cold rolling process. The evolution process of Cr fibers was studied, and when cold rolling reduction ε = 95%, the morphology of Cr fiber at different annealing temperature and the thermal stability of Cu-15Cr alloy were studied. Microstructure was also studied by scanning electron microscopy（SEM）. Meanwhile, the tensile strength of the alloy was tested by means of a precision universal tester, and the resistance value of the alloy was determined by using a digital micro-Euclidean instrument. The experimental results show that, with the increase of deformation, Cr dendrites evolve into homogeneous and parallelly arranged Cr fibers, and the cross-section of Cr fibers undergoes a ＂V＂ shape transition to ＂一＂ shape. In addition, spheroidization of the Cr fibers occurs on edges and extends to the center as annealing temperature rises. Moreover, the Cr fibers remains stable when the annealing temperature is below 550 ℃. Furthermore, the tensile strength of Cu-15Cr alloy decreases gradually as the annealing temperature increases, while the electrical conductivity maximizes when annealing at 550 ℃. Our study also shows that Cu-15Cr alloy has obtained a better comprehensive performance with tensile strength of 656 MPa and electrical conductivity of 82%IACS after annealing at 450 ℃.展开更多
基金Project(11YZ112)supported by Innovation Project of Shanghai Educational Committee in ChinaProject(J50503)supported by Shanghai Municipal Education Commission in China+1 种基金Project(10JC1411800)supported by Key Basic Research Project of Shanghai Committee of Science and Technology in ChinaProject(JWCXSL1101)supported by Shanghai Graduate Innovation Fund in China
文摘The vacuum medium-frequency induction melting technology was employed to prepare the Cu-15%Cr-0.24%Zr alloy. The scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, transmission electron microscopy （TEM） and high-resolution transmission electron microscopy （HRTEM） were used to analyze the phase composition, morphology and structure of the alloy. The results reveal that the as-cast structure of the alloy consists of Cu matrix, Cr dendrite, eutectic Cr and Zr-rich phase. A large number of Cr-precipitated phases occur in the Cu matrix, and Cu5Zr particles can be found in the grain boundary of Cu matrix. The HRTEM images prove that there is a semi-coherent relationship between Cu5Zr and Cu matrix.
基金Funded by the Key Project of the Ministry of Education of China(No.109061)the National Natural Science Foundation of China(No.10874118)the“SMC Young Star”Scientist Program of Shanghai Jiao Tong University
文摘The Cu-15Cr in-situ fiber-reinforced composites sheets were prepared by cold drawing combined with cold rolling process. The evolution process of Cr fibers was studied, and when cold rolling reduction ε = 95%, the morphology of Cr fiber at different annealing temperature and the thermal stability of Cu-15Cr alloy were studied. Microstructure was also studied by scanning electron microscopy（SEM）. Meanwhile, the tensile strength of the alloy was tested by means of a precision universal tester, and the resistance value of the alloy was determined by using a digital micro-Euclidean instrument. The experimental results show that, with the increase of deformation, Cr dendrites evolve into homogeneous and parallelly arranged Cr fibers, and the cross-section of Cr fibers undergoes a ＂V＂ shape transition to ＂一＂ shape. In addition, spheroidization of the Cr fibers occurs on edges and extends to the center as annealing temperature rises. Moreover, the Cr fibers remains stable when the annealing temperature is below 550 ℃. Furthermore, the tensile strength of Cu-15Cr alloy decreases gradually as the annealing temperature increases, while the electrical conductivity maximizes when annealing at 550 ℃. Our study also shows that Cu-15Cr alloy has obtained a better comprehensive performance with tensile strength of 656 MPa and electrical conductivity of 82%IACS after annealing at 450 ℃.
