Evolution of Irradiation-Induced Defect Landscape through Edge Dislocation and Vacancy Loop Interactions in Tungsten
Abstract
Structural materials in fusion reactors develop irradiation-induced defect populations that govern their mechanical behaviour. While advanced microscopy provides detailed characterisation of such defects, their dynamic evolution through dislocation-defect interactions during plastic deformation remains unresolved. Here, we address this gap using molecular dynamics simulations to resolve dislocation-defect interaction mechanisms and the resulting evolution of defect morphology and obstacle strength. Tungsten is the leading candidate plasma-facing material for fusion reactors, where vacancy loops are common irradiation defects. Using vacancy loops as a prototype defect, we systematically investigate their interactions with edge dislocations by varying loop size, orientation, and dislocation-loop intersection position. Parallel loops exhibit three distinct evolution pathways: complete annihilation, transformation into weaker remnant defects, or defect transport, depending on the intersection position and loop size. In contrast, inclined closed loops undergo dislocation reactions that produce sessile ⟨010⟩ dislocation segments, leading to substantially higher obstacle strengths with little sensitivity to the intersection position. Repeated dislocation interactions further demonstrate that the defect landscape is not static: remnant defects can persist, transform, or lose their ability to impede subsequent dislocations, depending on the preceding interaction mechanism. These results show that the obstacle strength of a vacancy loop is governed not only by its initial size and orientation, but also by its interaction history and the resulting defect structure.
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BibTeX
@misc{mishra2026evolution,
title = {{Evolution of Irradiation-Induced Defect Landscape through Edge Dislocation and Vacancy Loop Interactions in Tungsten}},
author = {Soumya Mishra and Suchandrima Das},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2607.27375},
eprint = {2607.27375},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.27375},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Evolution of Irradiation-Induced Defect Landscape through Edge Dislocation and Vacancy Loop Interactions in Tungsten
AU - Soumya Mishra
AU - Suchandrima Das
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2607.27375
UR - https://arxiv.org/abs/2607.27375
AB - Structural materials in fusion reactors develop irradiation-induced defect populations that govern their mechanical behaviour. While advanced microscopy provides detailed characterisation of such defects, their dynamic evolution through dislocation-defect interactions during plastic deformation remains unresolved. Here, we address this gap using molecular dynamics simulations to resolve dislocation-defect interaction mechanisms and the resulting evolution of defect morphology and obstacle strength. Tungsten is the leading candidate plasma-facing material for fusion reactors, where vacancy loops are common irradiation defects. Using vacancy loops as a prototype defect, we systematically investigate their interactions with edge dislocations by varying loop size, orientation, and dislocation-loop intersection position. Parallel loops exhibit three distinct evolution pathways: complete annihilation, transformation into weaker remnant defects, or defect transport, depending on the intersection position and loop size. In contrast, inclined closed loops undergo dislocation reactions that produce sessile ⟨010⟩ dislocation segments, leading to substantially higher obstacle strengths with little sensitivity to the intersection position. Repeated dislocation interactions further demonstrate that the defect landscape is not static: remnant defects can persist, transform, or lose their ability to impede subsequent dislocations, depending on the preceding interaction mechanism. These results show that the obstacle strength of a vacancy loop is governed not only by its initial size and orientation, but also by its interaction history and the resulting defect structure.
ER -