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Surface effect on the screw dislocation mobility over the Peierls barrier |
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| Authors: | Xi Cheng Lei Zhang Xiaohui Liu |
| Affiliation: | 1. State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University , No. 800, Dongchuan Road, Shanghai 200240 , China;2. Department of Mechanical Engineering , Stanford University , CA 94305 , USA;3. Department of Materials Science and Engineering , Pennsylvania State University , PA 16802 , USA;4. State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University , No. 800, Dongchuan Road, Shanghai 200240 , China |
| Abstract: | The effect of the image force on the Peierls stress (τ p ) of a screw dislocation below a free surface is studied via a self-consistent semidiscrete variational Peierls–Nabarro model. The consequence of reduction in elastic energy and increase in stacking fault energy by the presence of the free surface is found to additively increase the Peierls stress (τ p ). This model gives a physical interpretation of the same tend observed in a recent molecular dynamic study, while previous continuum analysis predicted the opposite. |
| Keywords: | Peierls stress Peierls–Nabarro model dislocations surfaces thin films |