MECHANICAL-PROPERTIES AND MICROSTRUCTURES OF SUBMICRON CERMETS

The microstructures of submicron cermets were investigated in order to improve their mechanical properties. Cermets of the system TiC-TiN-WC-TaC-Mo2C-Ni-Co were sintered using very fine TiC powders. HIPed specimens showed higher transverse rupture strength and higher hardness than conventional ones. These cermets showed different microstructures compared to conventional cermets. The SEM image of cermet made from submicron TiC showed the decrease in the number of grains with a TiC core. The SEM and TEM images of cermets made from 0.3 mu m TiC showed many grains without cores. Its microstructure was much finer and more homogeneous than the others.