Influence of high energy milling and addition of Nb on the densification and microstructure of a WC-Cu composite

Full text: The unique properties of copper metal matrix composite reinforced by dispersion tungsten carbide particles (WC) are of great importance for several industrial applications, due to their excellent high temperature strength and good corrosion and fracture resistance. This composite is chemically and thermally very stable at high temperatures, as well as having excellent thermal and electrical conductivity properties. This work investigates the effect of high energy milling on the densification and microstructure of the composites WC-20% Cu and WC-18% Cu-2% Nb as well as an influence of the addition of niobium as a grain growth inhibitor. The effect of the compacting pressure and the sintering temperature of the powders prepared by milling and mechanical mixing in the density were also studied. XRD, SEM, and EDS investigations were conducted for the microstructural characterization of sintered samples. To analyze a presence of impurities in the initial powder and the as-milled powders, chemical analyzes of XRF and EDS were performed. A XRD analysis was used to detect as structure of crystalline. Amortization of the Cu and WC phases occurred, with a decrease in the crystalline phase due to milling, and inhibition of grain growth, both at temperatures, in the samples with Nb. Higher compaction pressure and higher sintering temperature show better results for densification of the material. (author)