Microstructure of Ti(C_0.7N_0.3)–Mo₂C–xNbC–Ni Cermets

Abstract

ABSTRACT

The microstructures of Ti(C_0.7N_0.3)–19Mo₂C-xNbC–24Ni cermets (x = 0, 5, 10, 15, 20) were studied. The microstructures of them consisted of hard phase with Ti(C, N) and solid soluted Ti(C, N), and Ni binder phase. The solid soluted Ti(C,N) surrounded Ti(C, N), namely, core-rim structures in the cermets with low NbC contents. The phase separation between Ti(CN) core and solid soluted Ti(C, N) occurs in the cermets with high NbC contents. As a result of TEM analysis, solid soluted Ti(C, N) nucleated surrouunding Ti(C, N) in the 5NbC, on the other hand, another site in the 20NbC. The content of Nb in solid soluted Ti(C, N) in the 20NbC was higher than that in 5NbC. The hard phase separation occurred when the lattice constant of solid soluted Ti(C, N) was beyond 4.328 Å.