About this Abstract |
Meeting |
2024 TMS Annual Meeting & Exhibition
|
Symposium
|
Defects and Interfaces: Modeling and Experiments
|
Presentation Title |
Ab Initio Investigation of the Screw Dislocation-hydrogen Interaction in BCC Tungsten and Iron |
Author(s) |
Pedro Borges, Emmanuel Clouet, Lisa Ventelon |
On-Site Speaker (Planned) |
Pedro Borges |
Abstract Scope |
We employ ab initio calculations to investigate the interaction between 1/2<111> screw dislocations and interstitial hydrogen atoms in bcc tungsten and iron. Different core reconstructions are evidenced, depending on the number of hydrogen atoms introduced inside the dislocation core, with corresponding interaction energies being highly attractive. Dislocation pinning in its reconstructed configuration is efficient for local hydrogen atomic fractions as low as 1/5. Other octahedral interstitial sites close to the reconstructed core are also attractive, contrary to the perfect bcc crystal where these sites are unstable and where hydrogen lies in the tetrahedral sites. Hydrogen recovers its bulk behavior only beyond the eighteenth neighbor octahedral sites. A simple pair interaction model is parameterized on ab initio calculations, which we combine with a mean-field approximation to predict the concentration profiles of hydrogen segregated in and around the dislocation core. This work is published at Acta Materialia. |
Proceedings Inclusion? |
Planned: |
Keywords |
Computational Materials Science & Engineering, |