1. Molecular dynamics simulations of the diffusion and coalescence of helium in tungsten
- Author
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Yulu Zhou, Ai-Hong Deng, Jun Wang, and Qing Hou
- Subjects
Nuclear and High Energy Physics ,Helium atom ,chemistry.chemical_element ,Tungsten ,Atmospheric temperature range ,Molecular physics ,Dissociation (chemistry) ,Atomic diffusion ,Molecular dynamics ,chemistry.chemical_compound ,Nuclear Energy and Engineering ,chemistry ,Physics::Atomic and Molecular Clusters ,General Materials Science ,Physics::Atomic Physics ,Liquid bubble ,Atomic physics ,Helium - Abstract
Molecular dynamics (MD) simulations are performed on the diffusion and coalescence of helium in tungsten. A new method for determining the effective capture radii (ECRs) and the dissociation energies of helium-related defects is proposed in this work. It is observed that the ECR of an interstitial helium atom trapping helium interstitials (denoted as He–Hen, n = 1–3) decreases with increasing temperature, except for He–He2 at T D3 > D4 at T < 500 K, which can be attributed to the disordered structure of He5. The Arrhenius relation describes the diffusion of Hen well in the temperature range from 300 K to 550 K, whereas the diffusion is not a standard thermally activated process at higher temperatures. Taken together, these results help elucidate the initial stage of helium bubble formation in tungsten as well as the requirements of long-term evolution methods such as KMC or RT models.
- Published
- 2014
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