No abstract

In a WC–Co specimen, the shape of WC crystals was a triangular prism with truncated corners. When VC was added to inhibit grain growth, the crystal shape changed to a triangular prism without truncation. This shape change was related to the variation of edge energy, which has a significant influence on the coarsening process of WC grains.

The simultaneous addition of 0.5 wt% Cr and Fe was found to enhance the densification of TiB 2 . The densities of specimens that were sintered for 2 h at 1800°and 1900°C were 97.6% and 98.8% of the theoretical value, respectively. The mechanical properties of the specimen sintered at 1800°C, which had a strength of 506 MPa and a fracture toughness of 6.16 MPa⅐m 1/2 , were much better than those observed in the specimen sintered at 1900°C.