Full density processing of complex WC-based cemented carbides

The present investigation was a study of the densification behaviour of some complex WC-based cemented carbides containing TiC/TiN. Sintering experiments showed that a fully dense product can be obtained from cemented carbides containing TiC by liquid phase sintering, but TiC addition to WC-10 Go-cemented carbide necessitated modification of the binder phase cobalt by incorporating nickel and molybdenum in order to give a uniform microstructure. The sintering atmosphere also had important effects on sintering behaviour, and TiC-containing cemented carbides were sintered successfully in either H-2 or vacuum. With TIN addition, the material had to be sintered in a H-2 + N-2 mixture to avoid denitrification of the nitrogen bearing component. It was virtually impossible to achieve full density in TiN-containing cemented carbides by liquid phase sintering alone. Hot isostatic pressing of such liquid phase sintered alloys, therefore, became essential.