Phase Formation and Densification in Ultrafast High‐Temperature Sintering of Multi‐Principal‐Element Carbides

ABSTRACT To address the challenge of inefficient synthesis of multi‐principal‐element transition metal carbides, this study demonstrates an efficient pathway using ultrafast high‐temperature sintering (UHS) to convert elemental precursors into dense, 2‐ to 9‐component solid solutions within minutes. Rapid densification results from a synergy between the high heating rate of UHS and the formation of a Cr 3 C 2 ‐based liquid phase. The formation of a single‐phase solid solution is governed by a thermo‐kinetic control mechanism, where thermodynamic drivers are ultimately constrained by kinetic barriers, such as the poor solubility of key components (e.g., ZrC) and the diffusion‐facilitating role of carbon vacancies. The resulting solid solutions exhibit excellent hardness (up to 38.6 GPa), but their fracture toughness is limited by process‐induced thermal stresses, a drawback partially mitigated by post‐sintering annealing. This work presents a promising approach for the high‐throughput fabrication and screening of these materials and provides critical insights into their non‐equilibrium sintering mechanisms.