Molecular dynamics simulation of the behavior of typical radiation defects under stress gradient field in tungsten

JZ Fang and LX Liu and N Gao and WY Hu and HQ Deng, JOURNAL OF APPLIED PHYSICS, 130, 125103 (2021).

DOI: 10.1063/5.0059748

In the fusion environment, a complex stress field is generated in materials, which affects the evolution of radiation defects. In this study, the behaviors of radiation-induced defects under the effect of stress gradient field in tungsten are carefully simulated at the atomic scale with the molecular dynamics (MD) method. It was found that the stress gradient field affects the migration properties of interstitial defects, resulting in the energy barriers changing with the stress and stress gradient. In the axial stress gradient field, the movement of the 1/2 < 111 > interstitial dislocation loop is significantly accelerated, and it tends to move toward the region where the stress is concentrated. Within the time scale of the classical MD simulation, the stress gradient has little effect on the migration of vacancies. These results suggested that the stress gradient would cause interstitial defects to accumulate to the region where the stress is concentrated, thereby significantly changing the properties of the tungsten materials. Published under an exclusive license by AIP Publishing. https://doi.org/10.1063/5.0059748

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