Research Of Short Carbon Fiber Surface Treatment And Preparation Of Cf/Al Composites By Powder Metallurgy

Carbon fibers have low density, high strength, high modulus, thermostability, low thermal expansion coefficient, and other fine properties. Carbon fiber reinforced aluminum composites take the advantages of carbon fiber and aluminum alloy.So they are widely used in automobile industry, aerospace, sports products and other fields.In this paper, surface treatment of carbon fibers was investiagted to solve the problems such as surface roughness of fiber, wetting and interfacial reaction between carbon fibers and aluminum matrix appeared in the preparation process. Short Carbon fiber reinforced aluminum mitrix composites were parepared with powder metallurgic method. The powder metallurgic process parameter and heat treatment processes of composites were optimized. The microstructure, physical properties and mechanical properties were investigated. The results show that:Thin silver coated carbon fibers were obtained by cutting, baking, rough, neutralization and sensitization-activation process. Copper coated carbon fibers were got by chemical copper plating process and electroplating process. The longer term use of rough, neutralization, sensitization and reduction solution don't change its pretreatment effect on the fibres while the longer term use of activation and composition of chemical copper plating solution will decrease its pretreatment effect. By improving the activation process and copper plating process of carbon fiber, above all of the treatment solution could be reused. The surface treatment cost of carbon fibers was reduced and the surface treatment efficiency was greatly increased.Short carbon fibers with copper coating were used to fabricate short carbon fibers reinforced 2024 aluminum alloy composites by powder metallurgy method. The influence of hot press temperature, pressure and the volume fraction of carbon fibres on the density, percent oil absorbency and Vickers-Hardness were analyzed and discussed. The results show that the Cf/Al composites have most excellent density at 600‰,40MPa in hot-pressing process. The Cf-2024 aluminum alloy mitrix composites with 1 vol.% carbon fiber shows the highest vickers hardness. By optimizing the heat treatment of the composites with different volume fraction of carbon fiber, the best aging time of the Cf/Al material was determined. The test results show that the hardness increased with carbon fiber and optimal aging time of composited is decreased by 2-4h as a result of addition of carbon fiber.