Abstract
An investigation was conducted to study the variation of properties of a WC–TiC–TaC–NbC–Co alloy with carbon content. Carbon content was varied by adding tungsten and/or carbon black to the powder mixture. Lattice parameter measurements by X-ray diffraction showed the maximum solubility of tungsten in cobalt to be ∼10%. Besides α-cobalt, the presence of ε-cobalt was also observed. There is little change in cobalt lattice parameters, hardness, and coercive force outside the region where three phases are present. Although toughness reaches a maximum above the stoichiometric carbon content, optimum machining performance is obtained at a rather lower carbon content. With 5–8% tungsten in solution in the binder, the binder strength is improved, which explains the satisfactory machining results. PM/0193
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