An Evaluation of Cu-B₄C Composites Manufactured by Powder Metallurgy

In this study, the influences of B₄C ratios on some mechanical and physical properties such as relative density, microhardness and electrical properties of cold pressed Cu-B₄C composites were investigated. Curve fitting is applied for the estimation of electrical conductivity. Commercial copper powders with 40 μm particle size were reinforced with B₄C, with particle size of 40 μm, at ratios of 1, 2, 3 wt.%, for improving mechanical properties of copper used as electrical conductor. Cu-B₄C composites have been fabricated by powder sintering process at a temperature of 900°C for 2 h. The presence of Cu and B₄C, which are dominant components in the sintered composites, were confirmed by X-ray diffraction analysis technique and SEM-EDS. Scanning electron microscope (SEM-EDS) has shown that B₄C particles are distributed homogenously in the copper matrix. The relative densities of Cu and Cu-B₄C composites, sintered at 900°C, ranged from 95.7 to 91.6%. Microhardness of composites ranged from 84.5 to 94.6 HB. It was observed that cold pressed Cu-1 wt.% B₄C composites revealed promising physical properties. Results of electrical conductivity measurement of Cu-B₄C composite material are compared to the results of the model and the overall accuracy level above 96% is obtained.