| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Steels in Extreme Environments
|
| Presentation Title |
Developing an Atomistic Corrosion Model of Austenitic Steel Alloys from Ab-Initio Simulations of MnCr2O4 and Cr2O3 |
| Author(s) |
R. Seaton Ullberg, Xueyang Bognarova, Michael R. Tonks, Simon R. Phillpot |
| On-Site Speaker (Planned) |
R. Seaton Ullberg |
| Abstract Scope |
High temperature oxidation of 21-2N steel alloy produces a multilayered oxide film containing MnCr2O4, Cr2O3, and Mn3O4. To understand how this multilayered film grows it is crucial to identify the prevalent defects and their likely diffusion pathways. In this work, the thermodynamics and kinetics of point defects in the MnCr2O4 and Cr2O3 systems are evaluated with density functional theory. High-temperature conditions consistent with the application domain are modeled by adjusting the ab-initio chemical potential values to fit thermochemical data. In MnCr2O4, Mn is found to be highly mobile via a vacancy mediated mechanism, and CrMn substitutions enable a more favorable migration pathway for Cr relative to diffusion along its native sublattice. In Cr2O3, Mn is found to readily form substitutions on the Cr sublattice thus enabling rapid vacancy mediated diffusion of MnCr defects. Finally, we propose a mechanistic model of diffusion in the multilayered film from simulation and experimental observation. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Computational Materials Science & Engineering, Environmental Effects, High-Temperature Materials |