Study On Preparation And Properties Of Aluminum Matrix Composites Reinforced By Short Carbon Fiber

Carbon fiber is one of popular advanced materials, its low thermal expansion coefficient,high strength, excellent properties such as wear resistance are used in more and more high-tech industries. Carbon fiber reinforced aluminum matrix composites have good wear resistance, low thermal expansion coefficient, excellent electrical conductivity, etc, what make it has a broad application prospects.This paper adopts the method of powder metallurgy to prepare carbon fiber reinforced aluminum matrix composites. In order to avoid the difference of invasive carbon fibers and aluminum substrate, reactions occur easily, the carbon fiber chemical copper plating is studied, copper plating process is optimized. And hot pressing method is used for the preparation of composites materials, studies the proper hot pressing process, and the thermal expansion coefficient, friction coefficient and wear rate of composites is studied, the experimental results show as follows:1. In the chemical copper plating, under the electric mechanical stirring, the best copper plating process is: CuSO4·5H2O concentration is 20g/L, EDTA-2Na concentration is 25g/L, sodium potassium tartrate concentration is 25g/L,formaldehyde concentration is 15g/L, bipyridine 15mg/L, potassium ferrocyanide20mg/L, sodium hydroxide 16g/L, temperature is 60℃, pH value is 12, the addition of carbon fiber is 3g/L.2. Carbon fiber has significant effect on the hardness, density, thermal expansion coefficient, friction coefficient and wear rate of aluminum matrix composites. The density of composites increased with the increase of carbon fiber mass fraction, the hardness is biggist(HB102.6) and tensile strength is 278 MPa when carbon fiber mass fraction is 5% after heat treatment. Aluminum base composites thermal expansion coefficient is influenced by the addition of carbon fiber, the thermal expansion coefficient of the composites after heat treatment 5% mass fraction of Cf than no Cf decreased by 47.4%. The friction coefficient of composites decreased gradually with the increase of mass fraction of carbon fiber. When the mass fraction of carbon fiber is5%, the wear rate of composites reached the minimum. Integrated the above, when the mass fraction of carbon fiber is 5%, the composites has the best comprehensive property.3. Carbon fiber reinforced aluminum matrix composites wear principle mainly areabrasive wear and adhesive wear, the reinforcing mechanism of carbon fiber mainly is grain refinement, load shifted and the constraint.