Thermodynamic stability of ß-phases in Zr-Nb alloys
We investigate the contribution of mixing enthalpy, configurational entropy, vibrational entropy, and electronic entropy towards the thermodynamic stability of ß-(Zr,Nb) phases, to explain discrepancies in experimental observation of irradiated Zr-Nb alloys. Mixing enthalpy, configurational entropy,...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/405396 |
| Acceso en línea: | https://hdl.handle.net/2117/405396 https://dx.doi.org/10.1103/PhysRevMaterials.7.113607 |
| Access Level: | acceso abierto |
| Palabra clave: | Thermodynamics Molecular dynamics Thermodynamics of mixing Entropy Ab initio molecular dynamics Termodinàmica Dinàmica molecular Àrees temàtiques de la UPC::Física |
| Sumario: | We investigate the contribution of mixing enthalpy, configurational entropy, vibrational entropy, and electronic entropy towards the thermodynamic stability of ß-(Zr,Nb) phases, to explain discrepancies in experimental observation of irradiated Zr-Nb alloys. Mixing enthalpy, configurational entropy, and electronic free energy alone are insufficient to explain the relative stability of these phases. This emphasises the need for accurate determination of the vibrational free energy contributions, which we calculated using ab initio molecular dynamics. Including vibrational free energy contributions predicts ß-Zr decomposition in to HCP-Zr and ß-Nb at temperatures below ~880 K, in line with experimental observations. The relative energy difference between ß-Zr decomposition between 600 and 1200 K is small (<0.1 eV/atom) and may explain the wide range of apparently stable ß phases observed in neutron and proton irradiated Zr-Nb alloys. Other factors that may contribute towards the stability of these phases are also discussed. |
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