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

Abstract

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.

GRAPHICAL ABSTRACT

IMPACT STATEMENT

Novel macro-gradient structures in the Ti(C, N)-based cermet systems were observed for the first time, and the thermodynamic mechanisms were elucidated from the perspective of denitrification-induced W solubility change.

KEYWORDS:

• Ti(C
• N)-based cermets
• supersaturated WC
• macro-gradient structures
• thermodynamic calculations

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work is financially supported by National Natural Science Foundation of China [grant numbers 52101108, 52101026, 51901114, 52171009, 52031017], Natural Science Foundation of Zhejiang Province [grant number LQ20E010004], Science and Technology Department of Jiangxi Province [grant number 20181ACE50008V], Organizational Department of the Ningbo Municipal Committee [grant number 3315 Innovation Team 2020A-03-C], Natural Science Foundation of Shandong Province [grant number ZR2020ZD05], and Qilu Young Scholar Program in Shandong University.