Modulating the microstructural and mechanical characteristics of copper-tungsten carbide composite powders by WC content and milling time

Composites produced with a copper matrix and reinforced with ceramic and refractory material have applicability in electrical conductors. This study investigated copper powder with addition of different concentrations of tungsten carbide (5, 10, 15 and 20 % by mass) prepared by high-energy milling (HEM) for 1, 2, 5, 10 and 20 h. The powders obtained were characterized by Scanning Electron Microscopy (SEM), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD) with Rietveld refinement and Powder Vickers microhardness. The morphology of the powders was changed by HEM, deforming the copper particles due to their ductility. The brittle tungsten carbide particles were fragmented, resulting in a homogeneous distribution in the metal matrix and the production of composite particles. The dispersion, homogenization and particle size were significantly influenced by the milling time and percentage of WC, as well as the different milling mechanisms were identified. The diffractograms revealed characteristic peaks of copper and tungsten carbide, and the Rietveld refinement of the XRD revealed very significant changes in the structures of the studied phases. Vickers microhardness showed a direct relationship with the amount of WC, milling time and dispersion of the WC phase in the Cu matrix.