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First-principles study of He trapping in η-Fe2C.

Authors :
Bing-Ling He
Jin-Long Wang
Zhi-Xue Tian
Li-Juan Jiang
Wei Song
Bin Wang
Source :
Chinese Physics B; Nov2016, Vol. 25 Issue 11, p1-1, 1p
Publication Year :
2016

Abstract

The distribution of He in η-Fe<subscript>2</subscript>C has been studied by first-principles calculations. The formation energies of interstitial He and substitutional He (replacing Fe) are 3.76 eV and 3.49 eV, respectively, which are remarkably smaller than those in bcc Fe, indicating that He is more soluble in η-Fe<subscript>2</subscript>C than in bcc Fe. The binding potencies of both a substitutional-interstitial He pair (1.28 eV) and a substitutional-substitutional He pair (0.76 eV) are significantly weaker than those in bcc Fe. The binding energy between the two He atoms in an interstitial–interstitial He pair (0.31 eV) is the same as that in bcc Fe, but the diffusion barrier of interstitial He (0.35 eV) is much larger than that in bcc Fe, suggesting that it is more difficult for the interstitial He atom to agglomerate in η-Fe<subscript>2</subscript>C than in bcc Fe. Thus, self-trapping of He in η-Fe<subscript>2</subscript>C is less powerful than that in bcc Fe. As a consequence, small and dense η-Fe<subscript>2</subscript>C particles in ferritic steels might serve as scattered trapping centers for He, slow down He bubble growth at the initial stage, and make the steel more swelling resistant. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
16741056
Volume :
25
Issue :
11
Database :
Complementary Index
Journal :
Chinese Physics B
Publication Type :
Academic Journal
Accession number :
119447453
Full Text :
https://doi.org/10.1088/1674-1056/25/11/116801