Effects of TiC Content on the Microstructure and Mechanical Property of WC-TiC-TaC Cemented Carbides

WC-TiC-TaC cemented carbides were fabricated by hot-pressed sintering at 1600. Effects of TiC content on the microstructure and mechanical properties of these cemented carbides were investigated. It was found that when TiC content was increased from 10wt% to 25wt%, both the average grain size and the Vickers hardness increased progressively, but both the flexural strength and the fracture toughness decreased gradually. The increase of Vickers hardness was attributed to the increase of TiC content and the hardness of TiC was higher than that of WC. The value of the highest Vickers hardness was 19.81 GPa. This work also showed that the highest flexural strength (1147.24 MPa) was ascribed to the fine and homogeneous grains, and that the highest fracture toughness (14.60 MPam 1/2 ) was due to the intensive coupled mechanism of the fine-grain toughening, crack deflection, crack branching, crack bridging, and toughness dimples.