Stability of the Two-phase Structure of the Hard Particles in Ti(C, N) Base Cermets and Diffusional Phenomena in Ti(C, N)-(Ti, Mo)C Diffusion Couples

Abstract

In order to study the phase stability of the hard particle grains in cermet cutting materials (Ti, Mo)(C, N)-Ni cermets were heat treated at 1393K for 7.2 × 10³ ks (2000h). The microstructurel changes were compared to the changes observed in nitrogen free (Ti, Mo)C-Ni cermets under otherwise identical conditions. (Ti, Mo)C-Ti(C, N) and (Ti, Mo)C-TiC diffusion couples were also prepared and heat treated at 2023 and 2173 K. Surprisingly, the (Ti, Mo)C-Ti(C, N) diffusion couple showed faster diffusion kinetics than the (Ti, Mo)C-TiC couple. A mechanism based on the chemical interaction of Mo and N atoms was proposed for this phenomenon.