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Wang L.,Henan University of Science and Technology | Wang L.,Henan Key Laboratory of Advanced Non Ferrous Metals Materials and Processing | Song K.,Henan University of Science and Technology | Song K.,Henan Key Laboratory of Advanced Non Ferrous Metals Materials and Processing | And 4 more authors.
Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys | Year: 2013

Three QCr0.5 wires with initial diameters of φ7 mm, φ5 mm and φ3 mm were cold drawn through different drawing passes with average strains of 0.05 and 0.1, respectively, to obtain the samples with different strain rate. The hardness and electrical conductivity of the samples obtained were measured and the microstructures were observed to understand the effects of initial diameter and drawing passes on microstructures and properties of QCr0.5 wires. The results show that the electrical conductivity of the cold drawn samples with different initial diameters is decreased with increasing in the strain, where the samples with φ7 mm have the maximum decrement value, the samples with φ5 mm are the second, and samples with φ3 mm have the lowest decrement value. The electrical conductivity of the samples with different drawing passes is decreased slowly with increasing in the strain under the same initial diameter, and the hardness is increased rapidly firstly, and then decreased slowly to a constant tendency. The decrease of electrical conductivity of the samples with average strain of 0.1 is more rapid than that one with the average strain of 0.05, and it is decreased by approximately 37%, however, the hardness is always the higher, where the highest hardness can reach to 114 HV. The microstructure observation reveals that the microstructure evolution of QCr0.5 is characterized by the uneven deformation of the internal and external structure, and the deformation degree of the external structure exhibits more severe. With the deformation increase, the deformation of internal and external structure tends to be homogeneous.


Zhang Y.,Henan University of Science and Technology | Zhang Y.,Henan Key Laboratory of Advanced Non Ferrous Metals Materials and Processing | Song K.,Henan University of Science and Technology | Song K.,Henan Key Laboratory of Advanced Non Ferrous Metals Materials and Processing | And 2 more authors.
Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys | Year: 2013

During QCr0.5 alloy internal oxidation, rare earth oxide powder was added in the oxide source to form rare earth atmosphere. After internal oxidation, the oxidation layer thickness, hardness and conductivity of the samples prepared were measured. In addition, the microstructure of the samples prepared was observed and analyzed. The results show that the oxidation layer and hardness of QCr0.5 alloy in rare earth atmosphere are higher than those without rare earths. Meanwhile, the electrical conductivity of QCr0.5 alloy is improved in rare earth atmosphere also.


Zheng C.,Henan University of Science and Technology | Zheng C.,Henan Key Laboratory of Advanced Non Ferrous Metals Materials and Processing | Song K.,Henan University of Science and Technology | Song K.,Henan Key Laboratory of Advanced Non Ferrous Metals Materials and Processing | And 7 more authors.
Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys | Year: 2011

The varied volumetric fraction nano-MgO particle reinforced copper matrix composites (MgO/Cu composites) were prepared by powder metallurgy technology. The hardness, density and electric conductivity of the MgO/Cu composites were examined, and its microstructure was observed. The results indicate that, with increasing in MgO particle content, density and electric conductivity of the composites are decreased, however, hardness is firstly increased and then decreased. The desirable comprehensive properties of the composites can be obtained with 2. 5% MgO particle. Reinforcement is uniformly and dispersedly distributed into the copper matrix after hot extrusion. With increasing in volumetric fraction of reinforcement, nano-particles appear together and gather in grain boundary of copper matrix.


Zhang Y.-M.,Henan University of Science and Technology | Zhang Y.-M.,Henan Key Laboratory of Advanced Non Ferrous Metals Materials and Processing | Liu W.-F.,China Aviation Optical Electrical Technology Co. | Zhao P.-F.,Henan University of Science and Technology | And 3 more authors.
Suxing Gongcheng Xuebao/Journal of Plasticity Engineering | Year: 2013

Cu-Cr alloy is used in high voltage isolating switch self-elastic contact finger parts as new material, which is superior to copper in strength and rigidity. Currently, many self-elastic contact fingers still use the traditional structure of copper, without advantage of new material. In this paper, triplet self-elastic contact finger was taken as objective. Based on material performance parameters of new Cu-Cr alloy, the structural analysis and sensitivity analysis were performed through finite element numerical simulation. The key parameter to influence structure of contact finger was determined as thickness. Then, structural parameters were optimized. According to the optimized structure, precision molding dies were designed, and qualified parts were produced. The comparison showed that after optimization the maximum equivalent stress was 315.37 MPa, the maximum shear stress was 181.24 MPa, and the maximum deformation was 2.55 mm, which satisfied the application requirement. The thickness was reduced to 3.43 mm from 5mm of copper, and the weight was reduced by 30% than that of traditional copper.

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