Study On Fabrication And Properties Of Carbon Fiber Reinforced Cu-Ti₃SiC₂ Composites

Carbon fiber possesses a series of outstanding properties, i.e., high specific strength, high modulus, low density, high temperature resistance, corrosion resistance, antifatigue, creep resistance, electrical conductivity, thermal conductivity, low coefficient of thermal expansion and fine self-lubricating, antifriction. It becomes one of the most important reinforced material. Carbon fiber reinforced copper matrix composite, with its excellent properties of high electrical conductivity, high thermal conductivity, self-lubricating, resisting electric-arc erosion and so on, is a promising functional composite.Ti₃SiC₂ is a novel layered ceramic material, it combines the merits of both the metals and ceramics. It has salient properties, such as low density, high melting point, nice electrical and thermal conductivity, high elastic modulus, high fracture toughness, oxidation resistance, thermal shock resistance and machinability. And more significantly, it has very low friction coefficient and nice self-lubricating properties . Ti₃SiC₂ is a promising ceramic reinforcement for copper. So the introduction of Ti₃SiC₂ to the copper matrix will exert the effect of dispersion strengthened copper, making the composites exhibit more excellent properties.This paper tried to combine the carbon fiber reinforced copper and Ti₃SiC₂ dispersion strengthened copper, prepared the carbon fiber reinforced Cu-Ti₃SiC₂ composites. This material may integrate the excellent properties of carbon fiber, copper and Ti₃SiC₂. So it becomes to a novel copper matrix functional composite worthy of study.The preparation of Ti₃SiC₂ ceramics powder has been studied. High purity Ti₃SiC₂ powders were fabricated by pressureless sintering from Ti/Si/C/Al elemental powders. In this paper, short carbon fiber reinforced Cu-Ti₃SiC₂ composites were prepared by hot pressing and powder metallurgy. Emphasis was placed on plating copper on carbon fiber and fabricating technology of the composite. And the density, relative density, hardness and electrical resistivity of the material were also researched.In the process of fabricating the composite, there are two key technical questions, which is the wetting property and homogeneous distribution of carbon fibers within the matrix. High-quality copper plating coating was obtained by using citrate-tartrateplating solution. And proper plating processing parameter had very important influence on effect of plating copper. Using wet mixing method to mix with carbon fibers, copper powders and Ti3SiC2 powders could disperse carbon fibers in the matrix homogeneously.With comparison, results demonstrated that hot pressing is a better method for fabricating carbon fiber reinforced Cu-Ti3SiC2 composites. And the optimal hot pressing parameter were: when Ti3SiC2 volume content is 10%, the optimum carbon fiber volume content is 8%.While Ti3SiC2 is 15%, the optimum carbon fiber volume content is 10%;The optimal sintering temperature is from 800"C to 850°C, pressure is 30MPa, soaking time is 90 minutes. The microstructure of the composites was investigated by using SEM. And the strengthen mechanism and fracture mechanics of the composites were analyzed.