The microstructure and the thermal expansion characteristics of Cu/SiCp composites

Copper/silicon carbide composites (Cu/SiCp) were made by the powder metallurgy method. Electroless plating was employed to deposit a copper film on SiCp powder before mixing with Cu powder in order to improve the bonding status between Cu and SiC particles during sintering. Thermal expansion property of as-formed product was measured in the temperature range from 50 to 550 °C. The results showed that copper coating on silicon carbide particles could render uniform distribution of SiCp in the copper matrix. The composites exhibited positive thermal hysteresis behavior when cooled down from the peak temperature to room temperature, which can be explained in terms of the residual stresses and the interfacial bonding between copper and silicon carbide. The magnitude of this strain was a function of the SiCp volume fraction and the number of thermal cycles. The thermal expansion property of composites was measured and compared with those predicted from various theoretical models.