Mechanical and Tribological Enhancement in Non‐Equimolar (TiZrHfTaV)C Ceramics via Secondary Phase Reinforcement

ABSTRACT

Precise compositional regulation is critical for optimizing the microstructure and mechanical properties of high‐entropy carbide ceramics (HECCs), since minor elemental ratio changes greatly affect phase stability, defect evolution, and mechanical behavior. The V molar ratio in (TiZrHfTaV)C HECCs was systematically tailored to elucidate its regulatory effects on phase composition, microstructure, mechanical properties, and tribological behaviors. The results reveal that reducing V content facilitates TiC dissolution, enabling a transition from multi‐phase to single‐phase, accompanied by grain coarsening and a slight decline in relative density. Notably, the moderate‐V sample delivers the optimal overall performance, achieving a flexural strength of 531.50 ± 91.72 MPa, fracture toughness of 4.11 ± 0.49 MPa·m ^1/2 , and outstanding tribological behavior. These improvements are attributed to the formation of TiC, dislocation as well as the formation of a uniform V‐rich tribo‐oxide layer. This work offers fundamental insights into the compositional design and performance optimization of HECCs for extreme service environment.