Insights of electronic structures, mechanical properties and thermal conductivities of TM₅SiB₂ (TM=V, Nb, and Ta) MAB phases

ABSTRACT

The electronic, elastic, and thermal properties of TM₅SiB₂ (TM = V, Nb, and Ta) MAB phases are calculated herein using first-principles calculations. The obtained electronic structures show that there are p-d hybridizations between B, Si, and TM atoms, and TM-B and TM-Si bonds are formed by the electrons transfer between TM and B, TM and Si. Elastic Modulus and elastic Anisotropy Index, three-dimensional surface construction, and two-dimensional projection are used to discuss the elastic anisotropy, and the results show that these TM₅SiB₂ MAB phases are anisotropic in elastic modulus with the order of V₅SiB₂ > Nb₅SiB₂ > Ta₅SiB₂. Besides, the Debye temperature and sound velocity of these TM₅SiB₂ are also analyzed. The thermal conductivities are obtained, and the thermal conductivity is also anisotropic and in the same order as elastic modulus.

KEYWORDS:

• First-principles calculations
• MAB phases
• mechanical properties
• thermal conductivity
• anisotropy

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study is supported by the Rare and Precious Metal Materials Genome Engineering Project of Yunnan Province under grant number 202002AB080001, Yunnan Ten Thousand Talents Plan Young & Elite Talents Project under grant number YNWR-QNBJ-2018-044 and the National Natural Science Foundation of China under grant number 51761023.