TiB₂ exhibits a unique combination of excellent properties that make it promising candidate for applications in extreme environments, where retention of strength at high temperatures is essential. Tailoring grain boundary properties by segregation is believed a prominent way to design high‐temperature performance of ceramics. In this work, segregation tendencies of solute elements, including Sc, Y, Zr, Hf, V, Nb, Ta, Cr, Mo, and W, in TiB₂ grain boundaries and the strengthening/weakening effects induced by segregations are investigated by first‐principles calculations. The results reveal that small atoms tend to segregate to grain boundary sites with local compression strains, while large atoms prefer grain boundary sites with local expansion strains. Deteriorated grain boundary strength is usually caused by additional expansion strain induced by segregation, while improved grain boundary strength results from either enhanced local bonding induced by segregation of small atoms or increased fracture strain due to segregation of large atoms. Cr and V, especially Cr, exhibit strong segregation tendency and improvement on grain boundary strength, which provides useful guidelines for the design of high performance TiB₂‐based materials.

中文翻译：

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设计基于高性能TiB2的材料的策略：通过固溶体偏析强化晶界

TiB ₂具有独特的优异性能组合，使其成为在高温下保持强度至关重要的极端环境中应用的有希望的候选者。通过偏析来调整晶界特性被认为是设计陶瓷高温性能的一种重要方法。在这项工作中，TiB _2中包括Sc，Y，Zr，Hf，V，Nb，Ta，Cr，Mo和W的溶质元素的偏析趋势通过第一性原理计算研究了晶界和偏析引起的强化/减弱作用。结果表明，小原子倾向于偏向具有局部压缩应变的晶界部位，而大原子倾向于具有局部膨胀应变的晶界部位。晶界强度的降低通常是由偏析引起的额外的膨胀应变引起的，而改善的晶界强度则是由于小原子的偏析引起的增强的局部键合或由于大原子的偏析导致的断裂应变的增加。Cr和V，尤其是Cr，表现出强烈的偏析趋势并改善了晶界强度，这为设计高性能TiB ₂基材料提供了有用的指导。