Study Of Fabrication, Microstructure And Properties Of Continuous Carbon Fibers Reinforced Copper Matrix Composites

In this thesis continuous fibers with high strength and high module was compounded with copper matrix to acquire continuous carbon fibers reinforced copper matrix composite (Cf/Cu) with high strength and high conductivity. Study on fabricating technology to acquire good properties, through discussing the relative between microstructure and properties, the mechanism of infiltrating and molding, we presented the main factors effect on the synthesis properties of Cf/Cu.To cope with the usual problem of fiber gathering during fabricating carbon fiber reinforced copper matrix composites, the author of this thesis exerted prestress along fibers in fiber premodel, which can control the uniformity of fiber distribution in matrix effectively during copper liquid infiltrating the fiber premodel.To improve the wetting quality between the fiber and the copper matrix, plated copper on fibers after oxidation in hot air by two steps methods instead of usual method including CuSO4 and H2SO4, and connected cathode on several spot. To increase the efficiency of electrical current and gain even and continuous copper coating, and the black core phenomena disappeared, and the bonding between copper coating and fiber became better assuring the good compositing characteristic in the following fabricating of Cf/Cu.Fabricated Cf/Cu through melt and infiltration in vacuum, and aerated inert gas in the course of melt and infiltration. Compared with general infiltration, the infiltration in vacuum can improve the filling ability of copper liquid to fiber premodel, and avoid the serious inadequate filling in usual casting, and avert the fiber quality damage following high pressure during infiltration under pressure. Vacuum condition and the adding of inert air not only optimized the outer atmosphere and improved the wetting quality, also avail to get rid of the impure gas during the course of melt and infiltration. Through melt and infiltration in vacuum, copper liquid can obtain good filling effect to fiber premodel, ihe casting defection was decreased markedly, and the damage and -fracture of fibers was deadened, and the synthetically properties of Cf/Cu were improved remarkably.In this thesis the maths model of the compositing of C/Cu was discussed and the main factors which affected on the quality of moulding. Through observing and analyzing the microstructure of C/Cu, the author considers that we can describe the moulding course by two academic model. Model one is produce crystal nucleolus inside copper matrix and grow by pushing fibers, and Model produce crystal nucleolus along fibers and grow unspontaneously along fibers.Through experiments measured the conductivity and the extruding strength along the direction parallel to fibers, and probed in the mechanism of fracture of C/Cu , and discussed the influential factors to the conductivity of C/Cu.