Ab initio study of elastic anisotropies and thermal conductivities of rhenium diborides in different crystal structures
| Autor: | Wei Liu, Ying Y. Liu, Zheng X. Yan, Yi X. Wang, Jian B. Gu |
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| Rok vydání: | 2020 |
| Předmět: |
Bulk modulus
Materials science General Chemical Engineering Ab initio Thermodynamics Modulus 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Shear modulus Phase (matter) Vickers hardness test Density functional theory 0210 nano-technology Anisotropy |
| Zdroj: | RSC Advances. 10:37142-37152 |
| ISSN: | 2046-2069 |
| DOI: | 10.1039/d0ra07633c |
| Popis: | The phase stabilities, elastic anisotropies, and thermal conductivities of ReB2 diborides under ambient conditions have been investigated by using density functional theory calculations. It was found that P63/mmc (hP6-ReB2), Pmmn (oP6-ReB2), Rm (hR3-ReB2), Rm (hR6-ReB2), and C2/m (mC12-ReB2) of ReB2 are both mechanically and dynamically stable, and the order of phase stability is hP6 > oP6 > hR3 > hR6 > mC12. Moreover, the calculated Vickers hardness showed that hP6-ReB2, oP6-ReB2, hR3-ReB2, and mC12-ReB2 were potential hard materials, while hR6-ReB2 could not be used as a candidate hard material. In addition, the elastic-dependent anisotropy properties of ReB2 in different crystal structures were also investigated. The results show that the anisotropic order of the Young's modulus and shear modulus of ReB2 is hR6 > mC12 > oP6 > hP6 > hR3, while that of the bulk modulus is mC12 > hR3 > hP6 > oP6 > hR6. Finally, by means of Clarke's and Cahill's models, the minimum thermal conductivities of ReB2 in different crystal structures were further evaluated, and the order of them is hR3 > hP6 > mC12 > oP6 > hR6. Moreover, the results show that all these ReB2 diborides exhibit relatively low thermal conductivities and are suitable for thermal insulation materials. |
| Databáze: | OpenAIRE |
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