Effect of (Ti, Nb)(C, N) solid-solution powder on microstructure and mechanical properties of Ti(C, N)-based cermets: key experiment aided by thermodynamic calculations

Abstract

The preparation of Ti(C, N)-based cermets using (Ti, Me)(C, N) solid-solution powder instead of the traditional Ti(C, N) + MeC mixtures has gradually become a popular research subject. By using a (Ti, Nb)(C, N) solid-solution powder and Ti(C, N) + NbC powder, the microstructures and mechanical properties of Ti(C, N)-based cermets were investigated in the present work with the guidance of thermodynamic calculations. The thermodynamic calculations indicated that the (Ti, Nb)(C, N) was thermodynamically less stable than the Ti(C, N), which led to a difference in the microstructures and properties of the cermets prepared using (Ti, Nb)(C, N) and Ti(C, N) + NbC. The cermet prepared using the (Ti, Nb)(C, N) solid-solution powder had a no/weak core–rim structure. Moreover, the surface binder-rich phases of the cermets prepared by the (Ti, Nb)(C, N) solid solution was thinner under vacuum sintering, which was beneficial for improving the surface quality of the cermets. The hardness values of the cermets prepared using (Ti, Nb)(C, N) were greater than those of the cermets prepared using Ti(C, N) + NbC, and the fracture toughness underwent no noticeable change.