The idea of high‐entropy alloys (HEAs) has profoundly stimulated the recent development of novel entropy‐stabilized ceramics. Herein we explore the local lattice distortion, one of the core effects in HEAs responsible for their extraordinary properties, in typical high‐entropy ceramic (HEC) carbides with single‐phase rock salt structures. We first quantify the local distortions based on first‐principles calculations, and then investigate their influences on the structural properties, lattice stability, electronic structures, mechanical deformation, defect energetics, and thermodynamic properties. Our results show that carbon generally exhibits the most substantial distortion. On average, large local distortion is found in (NbTiVZr)C and (MoNbTaVW)C. Such distortion plays a crucial role in stabilizing HECs by lowering their enthalpy of formation. The electronic structure of HECs depends strongly on the local distortion, which can enhance charge transfer between transition metals and carbon atoms. We further show that distortion makes HECs soft and ductile due to the delocalization of electronic charges. The formation energies of C vacancies decrease significantly due to local distortion, resulting in high concentrations of C vacancies. The presence of high‐concentration C vacancies release distortion and helps to retain the high strength of HECs. Finally, we show that lattice distortion has a great impact on the thermodynamic quantities of HECs, such as thermal expansion coefficient and Debye temperature.

中文翻译：

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从第一性原理计算高熵碳化陶瓷的晶格畸变

高熵合金（HEA）的思想深刻地刺激了新型熵稳定陶瓷的最新发展。在本文中，我们探讨了局部晶格畸变，这是HEA在具有单相岩盐结构的典型高熵陶瓷（HEC）碳化物中所具有的非凡性能的核心效应之一。我们首先基于第一性原理计算来量化局部变形，然后研究它们对结构特性，晶格稳定性，电子结构，机械变形，缺陷能学和热力学特性的影响。我们的结果表明，碳通常表现出最严重的变形。平均而言，在（NbTiVZr）C和（MoNbTaVW）C中发现较大的局部失真。这种变形通过降低HEC的形成焓在稳定HEC中起着关键作用。HEC的电子结构在很大程度上取决于局部畸变，这会增强过渡金属和碳原子之间的电荷转移。我们进一步表明，由于电荷的离域，畸变使HEC变得柔软且具有延展性。C空位的形成能由于局部变形而显着降低，导致高C空位浓度。高浓度C空位的存在会释放变形，并有助于保留HEC的高强度。最后，我们表明晶格畸变对HEC的热力学量有很大影响，例如热膨胀系数和Debye温度。我们进一步表明，由于电荷的离域，畸变使HEC变得柔软且具有延展性。C空位的形成能由于局部变形而显着降低，导致高C空位浓度。高浓度C空位的存在会释放变形，并有助于保留HEC的高强度。最后，我们表明晶格畸变对HEC的热力学量有很大影响，例如热膨胀系数和Debye温度。我们进一步表明，由于电荷的离域，畸变使HEC变得柔软且具有延展性。C空位的形成能由于局部变形而显着降低，导致高C空位浓度。高浓度C空位的存在会释放变形，并有助于保留HEC的高强度。最后，我们表明晶格畸变对HEC的热力学量有很大影响，例如热膨胀系数和Debye温度。