Mechanical and tribological properties of WC incorporated Ti(C, N)-based cermets

Abstract

Incorporation of additional carbides into the widely-used Ti(C, N)-based cermets constitutes an important aspect of materials optimization strategy to impart better service properties for mining and machining applications. In this work, Ti(C, N)-WC-Mo2C–TaC-(Ni, Co) cermets with the WC content varying from 5.77 wt% to 19.68 wt% were specifically designed based on thermodynamic calculations, and their mechanical and tribological properties were subsequently examined. The results show that the increase of WC content brought about a higher fraction of the white core phase, which also induced a rise in hardness (by ∼10%) but a decline in toughness (by ∼20%). In addition, decreased wear rates (by ∼80%) at both 25 °C and elevated temperatures (400 and 750 °C) were also noted on the cermets containing the highest WC concentration. The wear behavior was found to be controlled by the surface hardness at 25 °C whereas the extent of oxide tribolayer formation at high temperatures. Micro-Raman spectroscopic and transmission electron microscopic observations suggested that the favorable generation of oxide tribolayers consisting of TiO2 and WO3 nano-crystals contributed to the improved high-temperature tribological properties.