Effect of collision cascades on dislocations in tungsten: A molecular dynamics study
| Autor: | S. P. Fitzgerald, Jun Wang, Q. Hou, Min Li, Baoqin Fu |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Nuclear and High Energy Physics Materials science Condensed matter physics chemistry.chemical_element 02 engineering and technology Tungsten 021001 nanoscience & nanotechnology 01 natural sciences Crystallographic defect Condensed Matter::Materials Science Crystallography Molecular dynamics Dipole chemistry Cascade Vacancy defect 0103 physical sciences Climb Dislocation 0210 nano-technology Instrumentation |
| Zdroj: | Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 393:169-173 |
| ISSN: | 0168-583X |
| DOI: | 10.1016/j.nimb.2016.10.028 |
| Popis: | Tungsten (W) is the prime candidate material for the divertor and other plasma-facing components in DEMO. The point defects (i.e. vacancies and self-interstitials) produced in collision cascades caused by incident neutrons aggregate into dislocation loops (and voids), which strongly affect the mechanical properties. The point defects also interact with existing microstructural features, and understanding these processes is crucial for modelling the long term microstructural evolution of the material under fusion conditions. In this work, we performed molecular dynamics simulations of cascades interacting with initially straight edge dislocation dipoles. It was found that the residual vacancy number usually exceeds the residual interstitial number for cascades interacting with vacancy type dipoles, but for interstitial type dipoles these are close. We observed that a cascade near a dislocation promotes climb, i.e. it facilitates the movement of point defects along the climb direction. We also observed that the dislocations move easily along the glide direction, and that kinks are formed near the centre of the cascade, which then facilitate the movement of the dipoles. Some dipoles are sheared off by the cascade, and this is dependent on PKA energy, position, direction, and the width of dipole. |
| Databáze: | OpenAIRE |
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