The effect of tantalum on properties and structure of titanium carbonitride-based hardmetals

摘要

It is ascertained that introduction of tantalum (as carbide) into TiCN-Ni-Mo and TiCN-Ni-No-WC hardmetals elevates their strength, determined in the course of transverse rupture strength testing and steel milling. It is shown that sintering thestarting mixtures of titanium carbidonitride with nickel and molybdenum is followed by formation of a phase being named as "K-phase", mainly, in the form of "shell" on TiCN grains. This phase is a complex carbidonitride (Ti, Mo, Ta)CN according to results of micro X-ray spectral analysis (This structure is classified as "co-axial" as ft is established in the literature). The assumption is made that gust the phase above causes the elevated strength of titanium carbidonitride-based tantalum containinghardmetals with nickel-molybdenum binder. From this standpoint utilizing of preset fabricated the tantalum containing titanium carbidonitride (instead of TiCN) is suggested as a starting material in hardmetals processing.