About this Abstract |
Meeting |
2024 TMS Annual Meeting & Exhibition
|
Symposium
|
Defects and Interfaces: Modeling and Experiments
|
Presentation Title |
From Anti-Arrhenius to Arrhenius Behavior in a Dislocation-obstacle Bypass: Atomistic Simulations and Theoretical Investigation |
Author(s) |
Mohammad Nahavandian, Enrique Martinez, Soumit Sarkar |
On-Site Speaker (Planned) |
Mohammad Nahavandian |
Abstract Scope |
Dislocations are the primary carriers of plasticity in metallic material. Understanding the basic mechanisms for dislocation movement is hence paramount to predicting the material mechanical response. Relying on atomistic simulations, we observe a transition from anti-Arrhenius to Arrhenius behavior in the rate for an edge dislocation to overcome the elastic interaction with a prismatic loop in tungsten. Beyond the critical resolved shear stress, the dislocation shows an anti-Arrhenius behavior at low temperatures. However, as the temperature increases, the activation entropy starts to dominate, leading to a traditional Arrhenius behavior. We also have computed the activation entropy analytically along the minimum energy path following Schoeck’s formalism, matching the results from molecular dynamics simulations. We conclude that entropic effects need to be considered to obtain a complete understanding of processes involving dislocations bypassing elastic barriers. |
Proceedings Inclusion? |
Planned: |
Keywords |
Modeling and Simulation, Computational Materials Science & Engineering, |