About this Abstract |
Meeting |
2024 TMS Annual Meeting & Exhibition
|
Symposium
|
Computational Thermodynamics and Kinetics
|
Presentation Title |
Solute Induced Defect Phases Transformations in Mg Σ7 Grain Boundaries |
Author(s) |
Prince Mathews, Siyuan Zhang, Christina Scheu, Rebecca Janisch, Jörg Neugebauer, Tilmann Hickel |
On-Site Speaker (Planned) |
Prince Mathews |
Abstract Scope |
Grain boundaries (GBs) strongly influence materials properties and GB transformations invoked by segregation of solutes can alter mechanical performance. In this work, the Σ7 [0001]|21.78° GB in hcp Mg is investigated. Ab-initio simulations are performed as a function of temperature (quasi-harmonic approximation), stress and solute coverage. High-resolution transmission electron microscopy images show the segregation of Ga to this GB. To explore the underlying mechanisms, a complete set of Ga configurations at the GB is prescreened using an empirical potential. The low-energy configurations are then upscaled to accurate ab-initio calculations and the defect phase diagram is constructed as a function of Ga chemical potential. Ga triggers a transformation from T to A type in the dilute limit and a systematic transition of the preferred segregation sites is seen. The results are qualitatively in very good agreement with our experimental findings and physical mechanisms are provided to explain remaining discrepancies. |
Proceedings Inclusion? |
Planned: |
Keywords |
Magnesium, Modeling and Simulation, Phase Transformations |