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<p>This study systematically investigates the electronic properties, elastic anisotropy, and thermodynamic behavior of the ternary TaMB<sub>4</sub>(M = Ti, Zr, Hf) system using first-principles density functional theory. Electronic structure analysis reveals that these compounds exhibit hybrid metallic-covalent-ionic bonding characteristics and dynamic stability. Calculated elastic constants confirm their mechanical stability under ambient conditions without phase transitions. Three-dimensional elastic modulus surfaces and two-dimensional projections demonstrate significant anisotropy in the bulk modulus (B), shear modulus (G), and Young’s modulus (E). Thermodynamic simulations based on the quasi-harmonic Debye model indicate that the constant-pressure heat capacity (C<sub>p</sub>) and thermal expansion coefficient (α) decrease with increasing pressure under extreme conditions (0–100&#xa0;GPa and 0–2000&#xa0;K). Sound velocity analysis reveals that TaTiB<sub>4</sub> exhibits higher directional sound velocities compared to TaZrB<sub>4</sub> and TaHfB<sub>4</sub>, with the minimum thermal conductivity (k<sub>min</sub>) following the order TaTiB<sub>4</sub> &gt; TaZrB<sub>4</sub> &gt; TaHf<sub>4</sub>. These findings provide theoretical insights into the structure–property relationships of these transition metal borides, offering guidance for their potential applications under extreme environments.</p>

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Theoretical predictions of thermodynamics, elastic anisotropy and electronic properties of TaMB4(M = Ti, Zr, Hf)

  • 期刊论文

  • 发表日期：

    2025年10月30日

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  • Zhe Li,
  • Guo Zheng,
  • Zhengyi Li,
  • Zhaohui Han,
  • Yang Xu,
  • Lei Xu

摘要

This study systematically investigates the electronic properties, elastic anisotropy, and thermodynamic behavior of the ternary TaMB4(M = Ti, Zr, Hf) system using first-principles density functional theory. Electronic structure analysis reveals that these compounds exhibit hybrid metallic-covalent-ionic bonding characteristics and dynamic stability. Calculated elastic constants confirm their mechanical stability under ambient conditions without phase transitions. Three-dimensional elastic modulus surfaces and two-dimensional projections demonstrate significant anisotropy in the bulk modulus (B), shear modulus (G), and Young’s modulus (E). Thermodynamic simulations based on the quasi-harmonic Debye model indicate that the constant-pressure heat capacity (Cp) and thermal expansion coefficient (α) decrease with increasing pressure under extreme conditions (0–100 GPa and 0–2000 K). Sound velocity analysis reveals that TaTiB4 exhibits higher directional sound velocities compared to TaZrB4 and TaHfB4, with the minimum thermal conductivity (kmin) following the order TaTiB4 > TaZrB4 > TaHf4. These findings provide theoretical insights into the structure–property relationships of these transition metal borides, offering guidance for their potential applications under extreme environments.