Copper (Cu)-matrix composites combine the high electrical and thermal conductivities of Cu with the enhanced wear resistance and strength of the reinforcement material, and are therefore widely used for electrical contact applications in a diverse range of fields. In the current study, tungsten-reinforced copper (W—Cu) composite powders are fabricated using a novel electroless Cu plating process in which the homogeneity of the powder mixture is improved via the use of an ultrasonic agitation technique. The volume content of the tungsten particle reinforcement in the composite specimens is 3, 6, and 12 per cent, respectively, and standard powder metallurgical techniques are then applied to produce the final composite powders. The mechanical and electrical properties of the composite powders are evaluated at room temperature and at temperatures ranging from 100 to 300 °C. Fracture surfaces of the composite samples are ana-lysed using scanning electron microscopy. The results show that the mechanical properties of the W—Cu composite samples are significantly better than those of pure Cu specimens, particularly at higher temperatures. Furthermore, the addition of 3 vol% W particles to the W—Cu composite is found to yield a reduction of not more than 2 per cent in the electrical conductivity of the composite sample compared to that of a pure Cu specimen. Overall, the results indicate that the optimal mechanical and electrical properties are obtained by mixing pure Cu powder with 3 vol% of Cu-plated W particles with a mean dimension of 1 μm.
Effect of HPT processing followed by long term natural ageing on mechanical and electrical properties of commercially pure Cu
