Study on Metallurgically Prepared Copper-Coated Carbon Fibers Reinforced Aluminum Matrix Composites

Abstract

Carbon materials, like carbon fiber, carbon nanotubes and graphene, were widely used as promising reinforcements to strengthen aluminum matrix composites (AMCs). The dispersion of reinforcement in matrix and interface wettability between matrix and reinforcing phase have been key factors affecting AMCs properties. In this study, electroless copper-coated carbon fibers reinforced aluminum (Cu-Cf/Al) composites were prepared by spark plasma sintering processing followed by heat treatment. Microstructure and mechanical properties were investigated. Microstructure observation indicated that fibers distributed uniformly in the composites containing up to 9 wt% copper-coated carbon fibers (Cu-Cf). In addition, an interfacial layer of 50 nm thickness was formed between the fiber and Al matrix due to mutual diffusion of Cu and Al atoms. Vickers hardness, tensile strength and bending strength of 9 wt% Cu-Cf/Al composite increased from 40 to 93 HV, 59 to 190 MPa and 110 to 326 MPa, respectively, compared to Al matrix. The improved mechanical properties are ascribed to the synergistic effect of dispersion, precipitation and solution strengthening. However, the elongation of composite decreased as compared to that of Al matrix. Moreover, Cu-Cf/Al composite exhibits superior corrosion resistance over uncoated carbon fiber/Al composite but less than Al matrix.