Study on solid state of diffusion bonding for Cu/(SiC)p MMC using similar/dissimilar interlayer

• Main Authors: Hsiang-Fu Fan, 范富翔
• Other Authors: Cheng-Li Chuang
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/44234078447537527280

碩士 === 中山醫學大學 === 職業安全衛生學系碩士班 === 102 === The metal matrix composite (MMC) was widely used in automobile and aerospace. However it is difficult to machining and welding, the components was thus made to net shape or near-net-shape. To expand the application of MMC, the traditional fusion welding process was used to weld the components of MMC. However, it has several potential hazardous factors, high temperature, fume, toxic gases, and radiations. Those hazards will affect the labor’s health and safety. Furthermore, the density of reinforcement is lighter than that of metal matrix, thus a segregation defect would form when the traditional fusion welding process was applied to join the metal matrix composite. In this study, the solid state diffusion bonding process, hot pressing method was used to join Cu/(SiC)p metal matrix composite. To compare the different interlayers for bonding quality, aluminum foil and copper foil with a thickness 50 μm was selected as a bonding layer, and a direct bonding of Cu/(SiC)p MMC without using interlayer. The major bonding parameters of solid state diffusion bonding, bonding durations, bonding temperature, and fraction of reinforcement were investigated. The bonding strength of MMCs was evaluated using a shear test, the observation and compositions identified on the fracture surfaces were using optical microscopy (OM) and scanning electron microscope (SEM). The phase identified was using Electron Probe X-ray Microanalyzer (EPMA). Hardness measurements were conducted using a 100g load with a testing time of 15s. The experiment result showed that the Cu/(SiC)p MMCs bonded successfully using the hot pressing process. With increasing bonding temperature and bonding durations , the relative density increased and the shear strength increased. An elevated bonding temperature enhances the atomic interdiffusion between Cu/(SiC)p base metal and the Cu interlayer. However, at high fractional SiC of Cu/(SiC)p MMCs, its relative density and the shear strength were decreased because the SiC particles clusters at bonding interface to obstruct the atomic interdiffusion, and the delamination was formed at bonding interlayer. With increasing bonding durations, the atom has enough time to conduct atomic interdiffusion and to improve the bonded quality. A dissimilar interlayer to bond Cu/(SiC)p MMCs using the hot pressing process conducted, the crack was formed due to different of coefficient thermal expansion (CTE) between Cu/(SiC)p and Al interlayer. For Cu/(SiC)p MMCs bonded without interlayer, its bonding quality would be degreed when a high fractional SiC reinforcement in Cu/(SiC)p MMCs, because SiC particles at bonding interface would obstruct atomic interdiffusion from a good bonding strength. Therefore, a good bonding quality can be achieved for Cu/(SiC)p MMC bonding with the Cu interlayer.