About this Abstract |
Meeting |
2025 TMS Annual Meeting & Exhibition
|
Symposium
|
Computational Thermodynamics and Kinetics
|
Presentation Title |
Lattice dynamical stability of the body-centered cubic (BCC) structure in Born-von Karman (BvK) force constant parameter space |
Author(s) |
Amir Husen, Jorge A. Munoz |
On-Site Speaker (Planned) |
Jorge A. Munoz |
Abstract Scope |
The well-known Born conditions for mechanical stability adopt a simple form for cubic structures that is easy to compute and provides physical intuition. We attempt to discern a similar framework for inhomogeneous deformations produced by lattice vibrations based on the harmonic BvK model. We developed a genetic algorithm with BvK force constants as genes from which dynamical matrices were computed, and with a fitness function that penalized imaginary eigenfrequencies and crystal translations. We used the algorithm to find purposely obfuscated force constants for BCC iron consistent with published values. Simpler models up to second nearest-neighbors were employed to investigate trends in the dynamical stability of the BCC structure as the atomic mass and lattice parameter varied. Effective harmonic force constants obtained from ab initio molecular dynamics for BCC iron at high pressure and BCC tantalum at high temperature were performed to understand the physical origin of the trends. |
Proceedings Inclusion? |
Planned: |
Keywords |
Computational Materials Science & Engineering, Phase Transformations, Iron and Steel |