Improved Friction and Wear Properties of Al6061-Matrix Composites Reinforced by Cu-Ni Double-Layer-Coated Carbon Fibers

The friction and wear properties of an Al6061 alloy reinforced with carbon fibers (CF) modified with Cu-Ni bimetallic layers were researched. Cu-Ni double layers were applied to the CF by electroless plating and Al6061-matrix composites were prepared by powder metallurgy technology. The metal-CF/Al interfaces and post-dry-wear-testing wear loss weights, friction coefficients, worn surfaces, and wear debris were characterized. After T6 heat treatment, the interfacial bonding mechanism of Cu-Ni-CF changed from mechanical bonding to diffusion bonding and showed improved interfacial bonding strength because the Cu transition layer reduced the fiber damage caused by Ni diffusion. The metal–CF interfacial bonding strongly influenced the composite’s tribological properties. Compared to the Ni-CF/Al and Cu-CF/Al composites, the Cu-Ni-CF/Al composite showed the highest hardness, the lowest friction coefficient and wear rate, and the best load-carrying capacity. The wear mechanisms of Cu-Ni-CF/Al composite are mainly slight abrasive wear and adhesive wear.