The influence of intermetallic ordering on wear and indentation properties of TiC-Ni3Al cermets

Abstract Cermets based on titanium carbide with a nickel aluminide binder (TiC-Ni 3 Al) offer potential as substitutes for tungsten carbide (WC) based hardmetals due to their high wear and corrosion resistance at ambient and elevated temperatures. In the current work, the effects of post-sinter heat treatments (between 600 and 1340 °C) on atomic ordering of the Ni 3 Al have been assessed through Vickers indentation, scratch testing and computational modelling. Changes in the atomic structure are evidenced from X-ray diffraction by abrupt increases in the (111) and (200) peak intensities. An increase in Vickers hardness, from 1400 to 1530 HV, is observed as a result of heat treatment at 1200 °C. Furthermore, the scratch hardness value was improved from 11.89 to 18.12 GPa, with the main wear mechanisms being identified as TiC grain pull out and brittle fracture. Ordering transitions were subsequently related to the structural changes predicted through ab-initio modelling approaches.