| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Materials Processing Fundamentals: Thermodynamics and Rate Phenomena
|
| Presentation Title |
Role of Entropy and Langevin Friction in Dislocation Glide Mechanisms |
| Author(s) |
Mohammad Nahavandian, Liam Myhill, Nikhil Chandra Admal, Giacomo Po, Enrique Martinez |
| On-Site Speaker (Planned) |
Mohammad Nahavandian |
| Abstract Scope |
Thermal activation of dislocations is critical for predicting the mechanical response of materials under common experimental conditions. According to transition state theory (TST), the rate for the system to overcome free energy barriers depends on attempt frequency, activation free energy, and temperature. We computed the power spectrum of a dislocation dipole at various temperatures using Molecular Dynamics (MD) to relate it to attempt frequency. For small Langevin frictions, the power spectrum remains the same, but strong friction changes it. Rates computed dynamically show dependence on Langevin friction, increasing with weaker friction and showing more correlated events. Statically, using Schoeck’s formalism and computing minimum energy path, we found significant entropic effects. We employed Dislocation Dynamics (DD) to include stochastic forces and compared the computed rates with MD results. We analyzed the discretization of dislocation in the results for different temperatures and stresses, discussing agreements and differences between MD and DD. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Computational Materials Science & Engineering, Modeling and Simulation, Copper / Nickel / Cobalt |