Macro-gradient structures generated in Ti(C, N)-based cermets with supersaturated WC: an experimental and thermodynamic investigation

WC is an indispensable constituent when producing Ti(C, N)-based cermets, yet its role on microstructure and the mechanism remain blurred. Herein, based on the CALPHAD approach, we designed and synthesized the cermets containing unsaturated and supersaturated WC. Formation of a macro-gradient structure was observed, encompassing an undissolved WC area, a WC dissolution area, and a (Ti, W)(C, N) solid-solution area. Such a unique structure has not been reported in cermet systems, which originates from the denitrification-induced W solubility change in Ti(C, N), as clarified computationally. Thus, this work shows the usefulness of thermodynamic calculations in establishing composition-microstructure relationships in cermets.