Microstructure of the Ni binder phase in a TiC–Mo 2C–Ni cermet

Abstract

Cermets are wear resistant materials used in cutting tool applications. The materials are composed of hard phase grains surrounded by a tough binder phase. The mechanical properties are influenced by both phases and grain boundaries. In this work, the detailed microstructure of the Ni binder phase in a TiC–Mo 2C–Ni cermet has been studied using a combination of transmission electron microscopy techniques. A complex contrast was observed in the Ni binder when imaged in the transmission electron microscope. It was found to arise from a combination of dislocations and nanometer sized particles that were present in the Ni matrix. From electron diffraction the particles were identified as intermetallic Ni 3Ti ( P6 3/ mmc). This result was consistent with energy-dispersive microanalysis and thermodynamics. The orientation relationship between the hexagonal Ni 3Ti particles and the cubic Ni matrix was given by (0001)Ni 3Ti//(111)Ni and [ 1 ̄ 2 1 ̄ 0] Ni 3Ti// [1 1 ̄ 0] Ni.