Microstructure and mechanical properties of oscillatory pressure sintered WC ceramics with different carbon sources

In current work, effect of different carbon sources on densification and mechanical properties of WC ceramics was studied by using a new type of oscillatory pressure sintering technique. It was found that addition of 0.3 wt% carbon contributed not only to promoting densification of WC ceramics but also to inhibiting formation of W2C phase, thus considerably enhancing mechanical properties of such ceramics. The highest relative density of 99.76%, corresponding hardness of 26.31 GPa and fracture toughness of 6.85 MPa.m(1/2) were obtained for WC ceramics with graphite oxide nanosheets as carbon source; also, crack deflection, crack bridging and pulling-out of graphite oxide nanosheets were main toughening mechanisms of such ceramics. It was suggested that WC ceramics with high performances can be prepared by combination of oscillatory pressure sintering and carbon addition.