Fracture origin and intrinsic strength of ultra-fine TiC0.7N0.3-based cermet

Transverse rupture strength of Ti(C,N)-based cermets is largely affected by the fracture origins. In this paper, ultra-fine cermet of low binder content is prepared with 0.13 μm TiC0.7N0.3 powder, and the fracture origin of the cermet is studied. The results show that the oxygen content of the ultra-fine TiC0.7N0.3 powder can be decreased by heating it in vacuum sintering furnace; 90% of the fracture origins are pores, and there are also a few Ni pools and carbide aggregations. The intrinsic strength of the prepared ultra-fine TiC0.7N0.3-based cermet is calculated to be 5000 MPa, much larger than the measured transverse rupture strength; HIP process can decrease the size of pores, and improve the transverse rupture strength of ultra-fine TiC0.7N0.3-based cermet.