Effet de l'addition de Ti sur les propriétés structurelles, thermodynamiques et élastiques des alliages Tix (HfNbTaZr)(1-x)/4
| Autor: | Bhatti, Asif Iqbal, Al-Houcine, Marwa, Queyreau, Sylvain, Tingaud, David |
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| Přispěvatelé: | Bhatti, Asif Iqbal |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: |
Condensed Matter - Materials Science
Ti based alloys Material database Body-centered cubic (bcc) Random alloys [PHYS.PHYS.PHYS-COMP-PH] Physics [physics]/Physics [physics]/Computational Physics [physics.comp-ph] Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences Configurational entropy [PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] Density Functional Theory (DFT) Phase stability High entropy alloys Special Quasi-Random structures (SQSs) |
| Popis: | The structure and thermodynamic properties of $Ti_{x}(HfNbTaZr)_{(1-x)/4}$ refractory highly entropy multicomponent alloys have been studied using a comprehensive Monte-Carlo Special Quasi-random Structure (MCSQS) realization of the disordered atomic structure and DFT calculations. We have shown that to model the random structure in a small supercell, it is necessary to study a large space of random configurations with respect to the nearest shells. Mimicking the randomness with the many-body terms does not lead to significant improvements in the formation energy but modeling the random structure with the few nearest neighbor pairs leads to improvements in the formation energy. We have also demonstrated the existence of weak to intermediate SRO for equimolar compositions. Chemical ordering is studied by linking a large number of MCSQS realizations to DFT calculations, and the SRO results are rationalized in terms of the crystallographic structure of the element pairs and binary phase diagrams. The formation energy of $Ti_{x}(HfNbTaZr)_{(1-x)/4}$ alloys remains slightly positive for all $x$ when Ti is added. For $x$ > 0.5, a phase transition in favor of an hcp structure is observed in agreement with the Bo-Md diagram. A dual phase is predicted at $x$ = 0.5. The Ti content in this class of alloys appears to be a practical way to select the phase structure and tailor the structure and elastic properties to specific applications. |
| Databáze: | OpenAIRE |
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