Effect of TiC/TiN powder size on microstructure and properties of Ti(C, N)-based cermets

The influence of TiC/TiN powder sizes on the microstructure and mechanical properties of Ti(C, N)-based cermets has been studied. With the refinement of the raw powder size of TiC/TiN, the amount of solid solution element in Ni/Co binder increases, the grain sizes of hard phase become finer, and the number of grains with white cores increases. In the cermets made from fine powders, the transverse rupture strength is greatly improved. but the fracture toughness is slightly reduced. From crack propagation path and fractured surface observed by SEM, it is found that the transcrystalline fractures occur more in the cermets with coarse grains, while the intercrystalline or intergranular rupture appears more in the cermets with fine grains. (c) 2006 Elsevier B.V. All rights reserved.