Microstructural and mechanical properties of TiC0.5N0.5–70 mass% W cermet specimens with core–rim structure prepared by pressureless sintering

Our previous research has shown that the TiC 0.5 N 0.5 –W cermet (TW) specimens fabricated by the spark plasma sintering (SPS) of blended submicron TiC 0.5 N 0.5 and W powders exhibit a fine Ti(C,N) core–(Ti,W)(C,N) rim structure with grain sizes of less than 1 μm and much higher strengths than conventional heat-resistant tool materials from 1473 K to 2073 K. Moreover, TW cutting and friction stir spot welding (FSSW) tools have been found to exhibit much longer life spans than conventional heat-resistant tools for the high-speed cutting of super-duplex stainless steel round bars and the FSSW of cold-rolled low-carbon steel plates, respectively. In this study, the TW specimens with the fine core–rim structure were prepared by the pressureless sintering (PLS) of blended submicron TiC 0.5 N 0.5 –70 wt% W powder at 2373 K for 1 to 3 h to increase their mass productivity. Then, the microstructural and mechanical properties of the TW specimens prepared by PLS were compared with those prepared by SPS. The TW specimens prepared by PLS at 2373 K for 1 and 3 h exhibited almost the same core–rim microstructure, room-temperature (RT) compressive strength, and RT fracture toughness as those prepared by SPS at 2223 K under a sintering pressure of 40 MPa for 0.5 h.