Unveiling Entropy‐Driven Hard‐Tough Synergy Mechanisms in High‐Entropy Carbonitride Ceramics

作者：Long Zhao, Jialin Sun, Xiao Li, Chengqiang Fan, Zhaozhen Li, Linghang Zhu, Jun Zhao · 发表于：Rare Metals · 年份：2026 · DOI：10.1002/rar2.70605 · 研究领域：High Entropy Alloys Studies、Advanced ceramic materials synthesis、Boron and Carbon Nanomaterials Research

ABSTRACT High‐entropy ceramics manifested promise for extreme environments, yet their phase stability and mechanical synergy mechanisms remain elusive. Herein, entropy‐difference carbonitrides, including (TaTiV)CN, (TaTiVNb)CN, and (TaTiVNbHf)CN, were designed and consolidated via spark plasma sintering. An integrated multiscale approach combining DFT calculations, Bader charge analysis, thermodynamic modeling, and experiments elucidated their electronic origins, lattice distortion, diffusion‐controlled evolution, and mechanical responses. Nb/Hf co‐doping triggered electronic reconstruction, manifested as enhanced d‐p hybridization, homogenized charge transfer, and elevated elastic constants, collectively strengthening intrinsic bond rigidity and shear resistance. Concurrently, sequential diffusion balanced sintering energy with solid‐solution formation, yielding progressive grain refinement and the transition from intergranular to transgranular fracture. Controlled lattice micro‐strain and increased dislocation density raised energy barriers for dislocation glide and crack propagation, while residual HfO 2 particles imparted extrinsic toughening employing crack bridging and deflection. Summatively, the predominant hard‐tough synergy mechanisms include electronic reconstruction, sequential diffusion‐controlled grain refinement, and HfO 2 ‐induced extrinsic toughening. High‐entropy ceramic (TaTiVNbHf)CN achieved exceptional hardness (23.02 GPa), flexural strength (556.98 MPa),...