About this Abstract |
| Meeting |
2021 TMS Annual Meeting & Exhibition
|
| Symposium
|
Computational Thermodynamics and Kinetics
|
| Presentation Title |
Lattice Dynamics of FeTi at Simultaneous High Temperature and High Pressure from First Principles |
| Author(s) |
Adrian De la Rocha, Jorge A. Munoz, Armando Garcia, Vanessa Meraz, Bethuel Khamala, Bert de Jong, Yu-Hang Tang |
| On-Site Speaker (Planned) |
Jorge A. Munoz |
| Abstract Scope |
FeTi is a brittle intermetallic compound that is stable in a large temperature and pressure range: up to 1600 K and at least up to 55 GPa, respectively. FeTi maintains the CsCl structure throughout and its Fermi surface is very simple, but it shows a remarkable variety of interesting physics, such as an anomalous phonon softening with temperature that has been attributed to a thermally-driven electronic topological transition, and phonon modes with negative Grüneisen parameters in a large volume range upon compression. We investigated the finite temperature lattice dynamics of FeTi at several volumes by fitting effective force constants to distributions obtained from a set of density functional theory calculations with atomic configurations selected by a learning algorithm using a graph-kernel-based similarity metric that minimize superfluous calculation. The force constants generally increase with pressure, but the Ti-Ti 2nd nearest-neighbors transverse bonds are anharmonic and change nonlinearly owing to charge redistributions. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Computational Materials Science & Engineering, Machine Learning, Titanium |