Release Time:2019-03-12  Hits:

Indexed by: Journal Article

Date of Publication: 2017-08-01

Journal: JOURNAL OF NUCLEAR MATERIALS

Included Journals: Scopus、EI、SCIE

Volume: 492

Page Number: 134-141

ISSN: 0022-3115

Key Words: Noble gas; Fe; Interaction; Irradiation; First principles

Abstract: We investigate the energetics and clustering trend of noble gas atoms (He, Ne, and Ar) in bcc Fe, and their interactions with vacancy or H/He impurities using first-principles calculations. We determine the formation energy of single and double noble gas atoms inside Fe host lattice as well as the resulted volume changes. The Ne/Ar formation energy is two and three times that of He. The attraction between Ne/Ar and vacancy is stronger than He-vacancy, indicating higher dissolution energy of Ne/Ar. The interstitial Ne-Ne/Ar-Ar pairs have stronger attractions (-1.91 eV/-1.40 eV) than He-He (-037 eV), forming stable <110> configurations. Such strong attraction means that He/Ne/Ar tend to aggregate, which can be well explained by the lower electron density induced by interstitial noble gas atoms and its strong repulsion with Fe atoms. Moreover, H/He energetically prefers to occupy the tetrahedral sites nearby Ne/Ar atom. The attraction energies of He-Ne/He-Ar pairs (-1.01 eV/-0.85 eV) are much stronger than those of H-Ne/H-Ar (-0.22 eV/-0.10 eV) and their charge density differences are discussed. The distinct attraction strengths by various noble gas atoms provide a preliminary explanation for the difference in irradiation effects on Fe solid by He, Ne, Ar, and He+H/Ne+He. These findings improve our understanding about the behavior of noble gas atoms and gas bubble formation in iron under irradiation. (C) 2017 Elsevier B.V. All rights reserved.