Prediction of Pressure-Induced Structural Transition and Mechanical Properties of MgY from First-Principles Calculations
| Autor: | Feiwu Zhang, Zhi-Wen Lu, Xian-Chao Xun, Hai-Zhen Song, Da-Wei Zhou, Chun-Ying Pu |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Phase transition
Bulk modulus Materials science Physics and Astronomy (miscellaneous) Condensed matter physics Phonon 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Physics::Geophysics Condensed Matter::Materials Science symbols.namesake Brittleness Phase (matter) 0103 physical sciences symbols 010306 general physics 0210 nano-technology Ductility Anisotropy Debye model |
| Zdroj: | Communications in Theoretical Physics. 65:92-98 |
| ISSN: | 0253-6102 |
| Popis: | Using the particle swarm optimization algorithm on crystal structure prediction, we first predict that MgY alloy undergoes a first-order phase transition from CsCl phase to P4/NMM phase at about 55 GPa with a small volume collapse of 2.63%. The dynamical stability of P4/NMM phase at 55 GPa is evaluated by the phonon spectrum calculation and the electronic structure is discussed. The elastic constants are calculated, after which the bulk moduli, shear moduli, Young's modui, and Debye temperature are derived. The brittleness/ductile behavior, and anisotropy of two phases under pressure are discussed in details. Our results show that external pressure can change the brittle behavior to ductile at 10 GPa for CsCl phase and improve the ductility of MgY alloy. As pressure increases, the elastic anisotropy in shear of CsCl phase decreases, while that of P4/NMM phase remains nearly constant. The elastic anisotropic constructions of the directional dependences of reciprocals of bulk modulus and Young's modulus are also calculated and discussed. |
| Databáze: | OpenAIRE |
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