Calculation of helium defect clustering properties in iron using a multi-scale approach.

Journal Article · Sun Jan 01 04:00:00 EST 2006 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2006.02.016· OSTI ID:958746

Seletskaia, Tatiana ^[1]; Osetskiy, Yury N ^[1]; Stoller, Roger E ^[1]; Stocks, George Malcolm ^[1]

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1. ORNL

Electronic structure calculations were used to study the relaxation, formation and binding energies of small helium clusters in iron. We considered three He defect configurations: two He atoms in an interstitial position and two and three He atoms located in one vacancy. To study He-vacancy clusters containing more He atoms, we used a multi-scale approach and constructed an empirical potential fitted to both formation and relaxation energies of a single He defect and small He clusters obtained from the first principles calculations. The potential consists of a repulsive pair-interaction part and a many-body attractive term describing the cohesion. The potential was used to study stability of He-vacancy clusters at zero temperature. The binding energy of a He atom to a He-cluster varies from 1.3 eV to 1.9 eV depending on the cluster size. When more than six He atoms are placed into a vacancy an Fe self-interstitial atom (SIA) is produced. The SIA binding energy to a He-di-vacancy cluster decreases from 5.0 eV to 0.7 eV as the number of He atoms increases. The results obtained are consistent with experimental observations of helium desorption reported in the literature.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 958746
• Journal Information: Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Vol. 351; ISSN 0022-3115; ISSN JNUMAM
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ATOMS
BINDING ENERGY
DEFECTS
DESORPTION
ELECTRONIC STRUCTURE
HELIUM
INTERSTITIALS
IRON
RELAXATION
STABILITY