About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Chemistry and Physics of Interfaces
|
| Presentation Title |
Finite-size Effects in Grain Boundary Energetics and Mobility: Insights on Nucleation-limited Migration |
| Author(s) |
Sanad Alturk, Mohammadhossein Nahavandian, Nithin Mathew, Enrique Martinez, Jason R. Trelewicz, Spencer L. Thomas |
| On-Site Speaker (Planned) |
Spencer L. Thomas |
| Abstract Scope |
Bicrystals with periodic boundary conditions are a mainstay of computational grain boundary (GB) studies. However, mechanisms that govern GB migration imply size-dependent migration energetics and consequently GB mobility. Disconnection energy calculations show that this energy will keep increasing for an arbitrarily large system, posing prohibitively large barriers to disconnection nucleation.
Using Molecular Dynamics GB mobility simulations, Nudged Elastic Band, and activation entropy calculation on the Σ3 (112) symmetric tilt GB in BCC tungsten, the size effect on GB mobility and disconnection free energy are calculated and connected via rate theory. GB mobility can vary significantly as a function of cell dimension unless the disconnection critical nucleation radius is limited by large driving forces. Otherwise, large barriers can render the GB immobile. This critical radius is sensitive to driving force magnitude, vibrational entropy, and thermal expansion, posing novel obstacles to connecting measured nucleation barriers to GB migration. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Computational Materials Science & Engineering, Modeling and Simulation, Thin Films and Interfaces |