Lattice Distortion Enhanced Hardness in High‐Entropy Borides

作者：Yiwen Liu, Mengdong Ma, Wu Wang, Haifeng Tang, Hulei Yu, Lei Zhuang, Pingbo Xie, Yanhui Chu · 发表于：Advanced Functional Materials · 年份：2024 · DOI：10.1002/adfm.202416992 · 被引用次数：61 · 研究领域：Advanced materials and composites、Diamond and Carbon-based Materials Research、Metal and Thin Film Mechanics

Abstract Revealing the hardening mechanisms is crucial for facilitating the design of superhard high‐entropy borides. Taking high‐entropy diborides (HEB 2 ) as the prototype, the hardening mechanisms of high‐entropy borides are thoroughly investigated. Specifically, the equiatomic 4—9‐cation single‐phase HEB 2 ceramics (4—9HEB 2 ) are fabricated by an ultra‐fast high‐temperature sintering method. The experimental results show that the hardness of the as‐fabricated 4—9HEB 2 samples has an increasing tendency with the increase of metal components. With a combination of first‐principles calculations, machine‐learning‐potential‐based molecular dynamics simulations, and scanning transmission electron microscopy characterizations, lattice distortion is explicitly identified to be essential in hardening HEB 2 by increasing strain field fluctuation, enlarging atomic strain energy, and strengthening B─B bonds. The results unravel the hardening mechanisms of HEB 2 by intensifying lattice distortion, providing fascinating guidance for developing superhard high‐entropy borides.