Characterisation of WC-Co with cubic carbide additions

In order to understand the effect of cubic carbide additions on the microstructure of WC-Co, six different materials were manufactured using the same WC powder and milling time. Four of the powder mixtures contained additions of TiC, ZrC, NbC or TaC and one of the powder mixtures contained both TiC and ZrC. All materials were designed to contain 20 vol% cubic carbide and 10 vol% binder phase as sintered. A WC-Co reference material containing 10 vol% binder phase was also manufactured. With electron backscatter diffraction (EBSD) it was seen that the best effect of grain growth inhibition was achieved when TiC was added to the powder mixture. The materials with addition of both TiC and ZrC had the highest hardness and coercivity of the materials manufactured. The fraction of low energy Σ2 WC/WC grain boundaries was seen to decrease as the Ostwald ripening proceeded during sintering.