About this Abstract |
Meeting |
2024 TMS Annual Meeting & Exhibition
|
Symposium
|
Computational Thermodynamics and Kinetics
|
Presentation Title |
Thermodynamic Stability of β Phases in Zr-Nb Alloys |
Author(s) |
Vidur Tuli, Antoine Claisse, Claudio Cazorla, Patrick A. Burr |
On-Site Speaker (Planned) |
Vidur Tuli |
Abstract Scope |
There have been conflicting reports on the composition of secondary phases in Zr-Nb alloys, which seem to vary with processing and irradiation conditions, suggesting the thermodynamics of these competing phases are not well understood. We investigate the contribution of mixing enthalpy, configurational and electronic entropy towards the stability of β-(Zr,Nb) phases and find that these alone are insufficient to explain their formation. This emphasises the need for accurate determination of vibrational free energy contributions, which we calculated using ab-initio molecular dynamics. Vibrational free energy contributions lower the energy of all β phases and, within the uncertainty of free energy calculations, predicts stable β phases at temperatures above 600 K. The relative free energy difference between Zr-rich and Nb-rich β-phase composition is small and may explain the wide range of apparently-stable phases observed in neutron and proton irradiated alloys. Other possible contributions towards the stability of these phases are also discussed. |
Proceedings Inclusion? |
Planned: |
Keywords |
Modeling and Simulation, Nuclear Materials, Computational Materials Science & Engineering |