Formation of Core/Rim Structures in Ti(C,N)‐WC‐Ni Cermets via a Dissolution and Precipitation Process

Abstract

The core/rim structures of compounds in the Ti(C,N)‐ x WC‐20Ni system have been investigated to determine the effect of WC and nitrogen content on the microstructure of the system. In addition, the relative dissolution rate of WC to Ti(C,N) in the system was studied by analyzing the rim compositions. Variations in the WC content had a much‐lesser influence, as an additive, on the general microstructure than that of other carbides that have been used in previous studies. However, the nitrogen content in Ti(C 1− X N X ) had a significant effect on its microstructure. The composition of the rim structure was determined by the ratio of solutes that were dissolved in the liquid binder, under the given processing conditions. The dissolution rate of WC was ∼2 and 5 times faster than that of Ti(C,N) in the system at temperatures of 1300° and 1510°C, respectively. The results have been interpreted in terms of phase stability and precipitation phenomena.