Effect of Mo2C addition on the microstructure and fracture behavior of (W,Ti)C-based cemented carbides

The effect of Mo2C addition on the microstructure and fracture behavior of (W,Ti)C-based cemented carbides was systemically studied in this work. A weak core/rim structure existed in solid solution cemented carbides. The grain size of cemented carbides decreased with the increase of Mo2C content while excessive Mo2C addition would lead to the inhomogeneity of the grains. As the Mo2C content increased, the wettability between (W,Ti)C phase and Co phase was improved, and the porosity of cemented carbides decreased. The mechanical properties were improved with proper Mo2C addition, but more than 15 wt% Mo2C decreased the transverse rupture strength and fracture toughness. Results also revealed that less transgranular fracture and more intergranular fracture were observed with the increase of Mo2C addition. The optimized Mo2C content was 15 wt% for (W,Ti)C–xMo2C–15Co cemented carbides.