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

Copper alloy matrix composites containing uncoated, copper coated, and nickel 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 these composites was investigated to show the effect of the IBS. It was found that at lower temperatures, the coefficient of thermal expansion (CTE) decreased with increasing IBS; at intermediate temperatures, the CTE declined with temperature, but the decreasing rate differed depending on the IBS; at higher temperatures, a rapid increase in CTE was observed and the increasing rate was IBS dependent. The IBS was noted to influence the residual strains of the composites.