Effect of Production Route on the Microstructure and Mechanical Properties of Cu-SiCp Composites

In this study, Cu matrix composite materials reinforced with SiC particles (SiCp) at different contents were produced by two different powder metallurgy (PM) processes, being traditional sintering and hot pressing. For the composites to be produced, 5-25% SiCp by weight was added to pure Cu powder at different contents and powder mixtures were prepared. The mixtures prepared in the production with traditional sintering were shaped by 500 MPa pressure, and green compacts were sintered at different temperatures to determine the optimum sintering conditions. The specimen production with the hot pressing process was performed by keeping the prepared powder mixtures at 880 degrees C, under 20 MPa pressure for 5 min using a graphite mold. The density, microstructure and mechanical properties of the composites produced were examined. The microstructure examinations were performed with the scanning electron microscope, energy distribution spectrometer and X-ray analysis. Characterization techniques such as hardness measurements, 3-point bending test and impact test were used for the determination of mechanical properties. Increased SiCp content caused a decrease in relative density values for both samples produced through traditional sintering method and hot-pressed samples. Considerably high relative density values were achieved with the hot pressing process compared to traditional sintering. The microstructure examinations showed that in the composites produced, the SiCp reinforcement phase dispersed homogeneously in the Cu matrix that comprised of relatively small and equiaxed particles. The mechanical tests showed that hardness increased remarkably with the increasing SiCp content while bending strength and impact energy values decreased.