Abstract The influence of transition metals on the structural stability, mechanical and thermodynamics properties of Mo5SiB2 is studied by the first-principles calculations. Two doped types: TM(1) model and TM(2) model are discussed. Four doped transition metals: Cr, Nb, Re and W are considered. The calculated results show that these transition metals are thermodynamic and dynamical stability in Mo5SiB2 based on the doped formation energy and phonon dispersion curves. In particular, the TM(1)-doping is more thermodynamic stability than that of the TM(2)-doping because of the B-TM-B layered structure in TM(1) model. Compared to TM(2)-doped Mo5SiB2 ceramics, TM(1)-doped Mo5SiB2 ceramic shows the strong elastic modulus, high hardness and high Debye temperature due to the B-TM-B layered structure. The transition metal can enhance the melting point of Mo5SiB2 ceramics. The high-temperature thermodynamic properties of TM-doped Mo5SiB2 derive from the vibration of B atom and Si atom. The calculated results show that the elastic modulus, hardness and Debye temperature of W-doped Mo5SiB2 ceramic are larger than the Mo5SiB2 ceramics and the other TM-doped Mo5SiB2 ceramics due to the d -state of W. Therefore, we predict that W is a useful element to improve the overall performances of Mo5SiB2 ceramics.

中文翻译：

---

第一性原理计算合金元素对Mo5SiB2结构稳定性、弹性、硬度和热力学性能的影响

摘要 通过第一性原理计算研究了过渡金属对Mo5SiB2结构稳定性、力学性能和热力学性能的影响。讨论了两种掺杂类型：TM(1) 模型和 TM(2) 模型。考虑了四种掺杂的过渡金属：Cr、Nb、Re 和 W。计算结果表明，基于掺杂形成能和声子色散曲线，这些过渡金属在 Mo5SiB2 中具有热力学和动力学稳定性。特别是，由于 TM(1) 模型中的 B-TM-B 层状结构，TM(1)-掺杂比 TM(2)-掺杂具有更高的热力学稳定性。与 TM(2) 掺杂的 Mo5SiB2 陶瓷相比，TM(1) 掺杂的 Mo5SiB2 陶瓷由于 B-TM-B 层状结构而表现出强弹性模量、高硬度和高德拜温度。过渡金属可以提高Mo5SiB2陶瓷的熔点。TM 掺杂的Mo5SiB2 的高温热力学性质源于B 原子和Si 原子的振动。计算结果表明，由于 W 的 d 态，W 掺杂的 Mo5SiB2 陶瓷的弹性模量、硬度和德拜温度均大于 Mo5SiB2 陶瓷和其他 TM 掺杂的 Mo5SiB2 陶瓷。因此，我们预测 W 是是提高 Mo5SiB2 陶瓷整体性能的有用元素。