Process and progress of sintering behavior of Cu-Al₂O₃ composites

The sintering temperature plays a major role in determining the microstructural as well as mechanical properties of composite materials. Apart from temperature, there are many factors, such as reinforcement particle geometry and morphology, which directly affect the sintering behavior of the composites. This study emphasizes the role of reinforcement particle geometry in the differential sintering response of copper-alumina composite. The copper and alumina powders were blended, compacted and then sintered conventionally at various temperatures such as 900, 950 and 1000°C. The formation of an interfacial phase has been characterized by X-ray diffraction and scanning electron microscopy. The variations in hardness values were recorded with the variation of sintering temperature, and these have been correlated with the formation of the intermediate compound. The formation of an intermediate phase at 950°C, and the variation in the properties of the composite sketches the profile of interfacial kinetics of the copper-alumina interface when alumina is present as particulate. The decrease in hardness at 950°C indicates the formative stage of CuAlO₂, and then an increase in hardness at 1000°C indicates the strengthening effect of the interfacial compound.