Development of High Toughness and High Thermal Conductivity Cermet

Abstract

WC-based cemented carbides are widely used as cutting tool materials. Tungsten, a main component of the cemented carbides, is one of the rare metals and its production is concentrated in certain countries. Therefore, a development of cutting tool materials containing less tungsten is highly desired today. Although Ti(C,N)-based cermets have higher hardness and provide higher machined surface quality as compared to cemented carbides, their applications have been limited due to their low fracture toughness and thermal conductivity.

Mechanical properties of Ti(C,N)-based cermets using Ti(C,N) solid solution powders prepared by dissolving various transition carbide powders as the starting materials were studied. The cermet using the Ti(C,N) solid solution powder containing Ta and Nb had the highest hardness and fracture toughness in the all prepared samples. In addition, it was found that the Ti(C,N)-based cermet with an optimized WC content prepared by controlling the sintering condition and the texture had both high fracture toughness and thermal conductivity. Cutting tools of our developed cermet exhibited a comparable cutting performance with those of WC-based cemented carbides (ISO P30).