Effect of interfacial bonding strength on thermal expansion behaviour of PM Al2O3/copper alloy composites

Copper alloy matrix composites containing uncoated, copper coated, and nick el coated Al2O3, particles were produced by the PM technique. The resulting composites, Al2O3/Cu, (Al2O3)(Cu)/Cu, and (Al2O3)(Ni)/Cu showed different interfacial bonding strength (IBS). The thermal expansion behaviour of thes e composites was investigated to show the effect of the IBS. It was found t hat at lower temperatures, the coefficient of thermal expansion (CTE) decre ased with increasing IBS; at intermediate temperatures, the CTE declined wi th temperature, but the decreasing rate differed depending on the IBS; at h igher temperatures, a rapid increase in CTE was observed and the increasing rate was IBS dependent. The IBS was noted to influence the residual strain s of the composites.