About this Abstract |
Meeting |
2021 TMS Annual Meeting & Exhibition
|
Symposium
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Computational Thermodynamics and Kinetics
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Presentation Title |
Phonons and Transition-induced Plasticity of bcc Refractory High-entropy Alloys from First Principles |
Author(s) |
Yuji Ikeda, Prashanth Srinivasan, Blazej Grabowski, Fritz Körmann |
On-Site Speaker (Planned) |
Yuji Ikeda |
Abstract Scope |
Recent experimental studies report that some body-centered cubic (bcc) refractory high-entropy alloys (HEAs) exhibit transition-induced plasticity (TRIP) by transforming to the hexagonal closepacked (hcp) structure. Better understanding of phase transitions of such HEAs is therefore crucial to further improve the mechanical properties. We study the thermodynamic and dynamic stability of refractory HEAs based on first-principles calculations. Phonon dispersions are
simulated based on the band-unfolding technique and they reveal, e.g., softening behavior of ZrNbHf, an alloy featuring also large atomic displacements. A careful treatment of atomic relaxations of bcc HEAs found to be critical to understand the phase transition of these alloys. Phase stabilities of these HEAs also show a close connection to the valence-electron
concentration (VEC). Thermodynamic integration in combination with machine-learning interatomic potentials enables us to accurately compute the vibrational free energies of HEAs even near the melting temperature. |
Proceedings Inclusion? |
Planned: |