About this Abstract |
Meeting |
2023 TMS Annual Meeting & Exhibition
|
Symposium
|
Computational Thermodynamics and Kinetics
|
Presentation Title |
High Pressure Phonon Thermodynamics of B2-ordered Equiatomic Iron-vanadium (FeV) |
Author(s) |
Homero Reyes, Ravhi Kumar, Bimal K C, Russell Hemley, Jorge A. Munoz |
On-Site Speaker (Planned) |
Jorge A. Munoz |
Abstract Scope |
The iron-vanadium system has been studied extensively because of its rich magnetism and order-disorder phase transitions. We will present results obtained with density functional theory (DFT) for FeV at high pressure and for several temperatures. At 0K, the cubic structure becomes unstable at 30 GPa with respect to the atomic displacements of the transverse acoustic (TA) M5 phonon modes. The TA M5 phonon modes behave anomalously, softening with pressure and stiffening with temperature. We attribute the former to a charge build-up between 2NN vanadium atoms that preferentially screen certain ionic motions. This effect is delicate and is significantly weakened by thermal atomic disorder, explaining the latter. We obtained x-ray diffraction patterns in a diamond-anvil cell at 300K and up to 80 GPa and did not observe a phase transition, potentially indicating that the transition occurs at a lower temperature. |
Proceedings Inclusion? |
Planned: |
Keywords |
Computational Materials Science & Engineering, High-Entropy Alloys, High-Temperature Materials |