About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Algorithms Development in Materials Science and Engineering
|
| Presentation Title |
Rate Modeling of Thermally Activated Defect Evolution in BCC Fe using Transition State Theory |
| Author(s) |
Joshua Kempfert, Jonathan L Wormald, Ting Zhu |
| On-Site Speaker (Planned) |
Joshua Kempfert |
| Abstract Scope |
Defect evolution at experimental timescales is often dictated by thermally activated processes, such as vacancy hopping or kink-pair glide of a dislocation. However, the kinetics of these processes are difficult to investigate with molecular dynamics (MD) due to limitations in simulation time, often requiring high stress and/or temperature to accelerate the events. Alternatively, the rate can be predicted using an activation free energy, which can be approximated using potential energy surface (PES) computations of the activation energy and vibrational entropy, most commonly with harmonic transition state theory (HTST). However, HTST is often inconsistent with MD rates. We resolve this discrepancy using a generalization of HTST involving a variational dividing surface and corrections to the partition functions. Our rates show strong agreement with MD for a variety of unit processes, often without need for dynamical corrections, demonstrating that rates at finite temperature can be accurately modeled using PES computations. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Modeling and Simulation, Nuclear Materials, Other |