Papers by Keyword: Cu-Based Composites

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Authors: Tungwai Leo Ngai, Yuan Yuan Li, Zhao Yao Zhou
Abstract: Increasing density is the best way to increase the performance of powder metallurgy materials. Conventional powder metallurgy processing can produce copper green compacts with density less than 8.3g/cm3 (a relative density of 93%). Performances of these conventionally compacted materials are substantially lower than their full density counterparts. Warm compaction, which is a simple and economical forming process to prepare high density powder metallurgy parts or materials, was employed to develop a Ti3SiC2 particulate reinforced copper matrix composite with high strength, high electrical conductivity and good tribological behaviors. Ti3SiC2 particulate reinforced copper matrix composites, with 1.25, 2.5 and 5 mass% Ti3SiC2 were prepared by compacting powder with a pressure of 700 MPa at 145°C, then sintered at 1000°C under cracked ammonia atmosphere for 60 minutes. Their density, electrical conductivity and ultimate tensile strength decrease with the increase in particulate concentration, while hardness increases with the increase in particulate concentration. A small addition of Ti3SiC2 particulate can increase the hardness of the composite without losing much of electrical conductivity. The composite containing 1.25 mass% Ti3SiC2 has an ultimate tensile strength of 158 MPa, a hardness of HB 58, and an electrical resistivity of 3.91 x 10-8 Ω.m.
596
Authors: Gui Min Liu, Bin Li, Jian Hua Du, Xiao Hui Zheng
Abstract: The Carbon nano-tubes (CNTs) reinforced Cu-based (CNTs/Cu) composites were obtained by powder metallurgy processes. The effects of CNTs content on the microstructure, density and hardness of the Cu-based composites were investigated. The tribological properties of the composites were studied by using a ball/disk friction tester. The results indicate that the density values of the composites gradually decrease with the increment of CNTs content, while for the hardness values, firstly increase and then decrease; and the maximal hardness values was obtained when the composite contains 0.75% CNTs. The CNTs content exerts a great effect on the friction coefficient of the composite. It has been found that the anti-wear property of the CNTs/Cu composites is excellent, at the same time, the hardness and density values are also in the reasonable ranges when the CNTs content is relatively low. The concerning mechanism has been analyzed in the present paper.
262
Authors: Yuan Yuan Li, Tungwai Leo Ngai, Zhi Yu Xiao, Zhao Yao Zhou
2737
Authors: Tungwai Leo Ngai, Zhi Yu Xiao, Yuan Biao Wu, Yuan Yuan Li
Abstract: Conventional powder metallurgy processing can produce copper green compacts with density less than 8.3 g/cm3 (a relative density of 93%). Performances of these conventionally compacted materials are substantially lower than their full density counterparts. Warm compaction, which is a simple and economical forming process to prepare high density powder metallurgy parts or materials, was employed to develop a Ti3SiC2 particulate reinforced copper matrix composite with high density, high electrical conductivity and high strength. In order to clarify the warm compaction behaviors of copper powder and to optimize the warm compaction parameters, effects of lubricant concentration and compaction pressure on the green density of the copper compacts were studied. Copper compact with a green density of 8.57 g/cm3 can be obtained by compacting Cu powder with a pressure of 700 MPa at 145°C. After sintered at 1000°C under cracked ammonia atmosphere for 60 minutes, density of the sintered compact reached 8.83 g/cm3 (a relative density of 98.6%). Based on these fabrication parameters a Ti3SiC2 particulate reinforced copper matrix composite was prepared. Its density, electrical conductivity, ultimate tensile strength, elongation percentage and tribological behaviors were studied.
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