Quasi-aperiodic grain boundary phases of Σ5 tilt grain boundaries in refractory metals
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arXiv
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| Format: | Preprint |
| Publié: |
2025
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| _version_ | 1866913994499948544 |
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| author | Chen, Enze Frolov, Timofey |
| author_facet | Chen, Enze Frolov, Timofey |
| contents | We report new ground-state structures and phase transitions in $Σ$5[001] tilt grain boundaries (GBs) in body-centered cubic (BCC) refractory metals Nb, Ta, Mo, and W. $Σ$5 tilt GBs have been extensively investigated over the past several decades, with their ground-state structure -- composed of kite-shaped structural units -- previously thought to be well understood. By performing a rigorous GB structure search that optimizes the number of atoms in the boundary core, we predict new quasi-aperiodic "split kite" phases analogous to those previously found in GBs in face-centered cubic metals. Our results suggest that complex aperiodic phases of GBs appear to be a general phenomenon, as validated through density functional theory calculations. Moreover, the atoms in the split kite phase demonstrate distinct collective diffusion dynamics. Phase-contrast image simulations of split kites show better agreement with experimental observations, offering an alternative explanation for previous microscopy results and motivating future atomically resolved imaging of the GB structure. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_15723 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Quasi-aperiodic grain boundary phases of Σ5 tilt grain boundaries in refractory metals Chen, Enze Frolov, Timofey Materials Science We report new ground-state structures and phase transitions in $Σ$5[001] tilt grain boundaries (GBs) in body-centered cubic (BCC) refractory metals Nb, Ta, Mo, and W. $Σ$5 tilt GBs have been extensively investigated over the past several decades, with their ground-state structure -- composed of kite-shaped structural units -- previously thought to be well understood. By performing a rigorous GB structure search that optimizes the number of atoms in the boundary core, we predict new quasi-aperiodic "split kite" phases analogous to those previously found in GBs in face-centered cubic metals. Our results suggest that complex aperiodic phases of GBs appear to be a general phenomenon, as validated through density functional theory calculations. Moreover, the atoms in the split kite phase demonstrate distinct collective diffusion dynamics. Phase-contrast image simulations of split kites show better agreement with experimental observations, offering an alternative explanation for previous microscopy results and motivating future atomically resolved imaging of the GB structure. |
| title | Quasi-aperiodic grain boundary phases of Σ5 tilt grain boundaries in refractory metals |
| topic | Materials Science |
| url | https://arxiv.org/abs/2501.15723 |