Density-functional theory calculations based on conventional as well as hybrid exchange-correlation functionals have been carried out to study the properties of helium in various oxides (Al2O3, TiO2, Y2O3, YAP, YAG, YAM, MgO, CaO, BaO, SrO) as well as at oxide-iron interfaces. Helium interstitials in bulk oxides are shown to be energetically more favorable than substitutional helium, yet helium binds to existing vacancies. The solubility of He in oxides is systematically higher than in iron and scales with the free volume at the interstitial site nearly independently of the chemical composition of the oxide. In most oxides, He migration is significantly slower and He–He binding is much weaker than in iron. To quantify the solubility of helium at oxide-iron interfaces two prototypical systems are considered (Fe—MgO, Fe—FeO—MgO). In both cases, the He solubility is markedly enhanced in the interface compared to either of the bulk phases. The results of the calculations allow to construct a schematic energy landscape for He interstitials in iron. The implications of these results are discussed in the context of helium sequestration in oxide dispersion strengthened steels, including the effects of interfaces and lattice strain.

1.
K.
Ehrlich
,
Philos. Trans. R. Soc. London, Ser. A
357
,
595
(
1999
).
2.
E. E.
Bloom
,
J. T.
Busby
,
C. E.
Duty
,
P. J.
Maziasz
,
T. E.
McGreevy
,
B. E.
Nelson
,
B. A.
Pint
,
P. F.
Tortorelli
, and
S. J.
Zinkle
,
J. Nucl. Mater.
367–370
,
1
(
2007
).
3.
G.
Odette
,
M.
Alinger
, and
B.
Wirth
,
Annu. Rev. Mater. Res.
38
,
471
(
2008
).
4.
T.
Seletskaia
,
Y.
Osetsky
,
R. E.
Stoller
, and
G. M.
Stocks
,
Phys. Rev. Lett.
94
,
046403
(
2005
).
5.
C. C.
Fu
and
F.
Willaime
,
Phys. Rev. B
72
,
064117
(
2005
).
6.
P.
Erhart
and
J.
Marian
,
J. Nucl. Mater.
414
,
426
(
2011
).
7.
S.
Ukai
,
T.
Nishida
,
H.
Okada
,
T.
Okuda
,
M.
Fujiwara
, and
K.
Asabe
,
J. Nucl. Sci. Technol.
34
,
256
(
1997
).
8.
S.
Ukai
,
T.
Nishida
,
T.
Okuda
, and
T.
Yoshitake
,
J. Nucl. Sci. Technol.
35
,
294
(
1998
).
9.
R.
Kasada
,
N.
Toda
,
K.
Yutani
,
H. S.
Cho
,
H.
Kishimoto
, and
A.
Kimura
,
J. Nucl. Mater.
367–370
,
222
(
2007
).
10.
C. L.
Fu
,
M.
Krcmar
,
G. S.
Painter
, and
X. Q.
Chen
,
Phys. Rev. Lett.
99
,
225502
(
2007
).
11.
E. A.
Marquis
,
Appl. Phys. Lett.
93
,
181904
(
2008
).
12.
Y.
Jiang
,
J. R.
Smith
, and
G. R.
Odette
,
Phys. Rev. B
79
,
064103
(
2009
).
13.
L. K.
Mansur
,
“Kinetics of nonhomogenous processes,”
in
Mechanisms and Kinetics of Radiation Effects in Metals and Alloys
(
Wiley-Intersciences
,
New York
,
1987
), p.
377
.
14.
J.
Marian
and
V.
Bulatov
,
J. Nucl. Mater.
415
,
84
(
2011
).
15.
L. L.
Hsiung
,
M. J.
Fluss
,
S. J.
Tumey
,
B. W.
Choi
,
Y.
Serruys
,
F.
Willaime
, and
A.
Kimura
,
Phys. Rev. B
82
,
184103
(
2010
).
16.
D.
Gryaznov
,
S.
Rashkeev
,
E.
Kotomin
,
E.
Heifets
, and
Y.
Zhukovskii
,
Nucl. Instrum. Methods. Phys. Res. B
268
,
3090
(
2010
).
17.
W.
Cheng
,
M.
Ying
,
F.
Zhang
,
H.
Zhou
, and
S.
Ren
,
Nucl. Instrum. Meth. Phys. Res. B
269
,
2067
(
2011
).
19.
S. B.
Zhang
and
J. E.
Northrup
,
Phys. Rev. Lett.
67
,
2339
(
1991
).
20.
P.
Erhart
,
D.
Åberg
, and
V.
Lordi
,
Phys. Rev. B
81
,
195216
(
2010
).
21.
P.
Erhart
and
K.
Albe
,
J. Appl. Phys.
104
,
044315
(
2008
).
22.
A. R.
Allnatt
and
A. B.
Lidiard
,
Atomic Transport in Solids
(
Cambridge University Press
,
Cambridge
,
2003
).
23.
P. E.
Blöchl
,
Phys. Rev. B
50
,
17953
(
1994
).
24.
G.
Kresse
and
D.
Joubert
,
Phys. Rev. B
59
,
1758
(
1999
).
25.
G.
Kresse
and
J.
Hafner
,
Phys. Rev. B
47
,
558
(
1993
).
26.
G.
Kresse
and
J.
Hafner
,
Phys. Rev. B
49
,
14251
(
1994
).
27.
G.
Kresse
and
J.
Furthmüller
,
Phys. Rev. B
54
,
11169
(
1996
).
28.
G.
Kresse
and
J.
Furthmüller
,
Comput. Mater. Sci.
6
,
15
(
1996
).
29.
J. P.
Perdew
,
K.
Burke
, and
M.
Ernzerhof
,
Phys. Rev. Lett.
77
,
3865
(
1996
);
[PubMed]
Erratum
,
Phys. Rev. Lett.
78
,
1396
E
(
1997
).
30.
J.
Heyd
,
G. E.
Scuseria
, and
M.
Ernzerhof
,
J. Chem. Phys.
118
,
8207
(
2003
);
Erratum
,
J. Chem. Phys.
124
,
219906
(
2006
).
31.
G.
Makov
and
M. C.
Payne
,
Phys. Rev. B
51
,
4014
(
1995
).
32.
G.
Henkelman
and
H.
Jónsson
,
J. Chem. Phys.
113
,
9978
(
2000
).
33.
G.
Henkelman
,
B. P.
Uberuaga
, and
H.
Jónsson
,
J. Chem. Phys.
113
,
9901
(
2000
).
34.
D. H. R.
Fors
and
G.
Wahnström
,
Phys. Rev. B
82
,
195410
(
2010
).
35.
P.
Erhart
,
A.
Klein
, and
K.
Albe
,
Phys. Rev. B
72
,
085213
(
2005
).
36.
P.
Agoston
,
K.
Albe
,
R. M.
Nieminen
, and
M. J.
Puska
,
Phys. Rev. Lett.
103
,
245501
(
2009
).
37.
In these materials, the oxygen vacancy also exhibits negative-U type character with the +1 charge state being unstable with respect to the +2 and 0 charge states.
38.
Voronoi volumes were obtained using the voro++ software, see Refs. 64 and 65.
39.
Titania represents a special case because of its strong tetragonal anisotropy that is also apparent from, e.g., the dielectric and elastic constants.
40.
In body-centered cubic iron, He atoms occupy tetrahedral interstitial sites equivalent to Wyckoff sites 12d resulting in a density of 0.53 sites/Å3.
41.
In general, the interface dislocation network will provide additional sites for He interstitials, but this effect is ignored in the present study.
42.
P.
Luches
,
S.
Benedetti
,
M.
Liberati
,
F.
Boscherini
,
I.
Pronin
, and
S.
Valeri
,
Surf. Sci.
583
,
191
(
2005
).
43.
X. B.
Feng
,
O.
Bengone
,
M.
Alouani
,
I.
Rungger
, and
S.
Sanvito
,
Phys. Rev. B
79
,
214432
(
2009
).
44.
K.
Nakamura
,
T.
Akiyama
,
T.
Ito
,
M.
Weinert
, and
A. J.
Freeman
,
Phys. Rev. B
81
,
220409
R
(
2010
).
45.
H.
Yang
,
M.
Chshiev
,
A.
Kalitsov
,
A.
Schuhl
, and
W.
Butler
,
Appl. Phys. Lett.
96
,
262509
(
2010
).
46.
Y.
Wang
,
J.
Zhang
,
X. G.
Zhang
,
H. P.
Cheng
, and
X. F.
Han
,
Phys. Rev. B
82
,
054405
(
2010
).
47.
The direct effect of tetragonal strain on the formation energies of He interstitials in iron was tested by considering volume conserving deformation (effectively treating the material as if it had a Poisson ratio of 0.5). For a linear strain of 5% the formation energy and free volume change by only 0.16 eV and 1.5%, respectively.
48.
P.
Erhart
(unpublished).
49.
50.
N.
Ishizawa
,
T.
Miyata
,
I.
Minato
,
F.
Marumo
, and
S.
Iwai
,
Acta Crystallogr
36
,
228
(
1980
).
51.
J. K.
Burdett
,
T.
Hughbanks
,
G. J.
Miller
,
J.
Richardson
,
W.
James
, and
J. V.
Smith
,
J. Am. Chem. Soc.
109
,
3639
(
1987
).
52.
D. C.
Cronemeyer
,
Phys. Rev.
87
,
876
(
1952
).
53.
R. A.
Parker
,
Phys. Rev.
124
,
1719
(
1961
).
54.
G.
Baldinozzi
,
J.
Berar
, and
G.
Calvarin
,
Mater. Sci. Forum
278–2
,
680
(
1998
).
55.
A.
Ohta
,
M.
Yamaoka
, and
S.
Miyazaki
,
Microelectron. Eng.
72
,
154
(
2004
).
56.
C. S. G.
Cousins
,
J. Phys. C
14
,
1585
(
1981
).
57.
N. L.
Ross
,
Phase Transitions
58
,
27
(
1996
).
58.
A.
Nakatsuka
,
A.
Yoshiasa
, and
T.
Yamanaka
,
Acta Crystallogr.
55
,
266
(
1999
).
59.
H.
Yamane
,
M.
Omori
, and
T.
Hirai
,
J. Mater. Sci. Lett.
14
,
470
(
1995
).
60.
In the international crystallographic database some records for this structure are provided in the Pbnm setting. The Pnma and Pbnm settings are equivalent and can be easily transformed into each by swapping the axes. The Bilbao crystallographic server (http://www.cryst.ehu.es) uses the Pnma setting.
61.
Landolt-Börnstein: Numerical Data and Functional Relationships in Science and Technology, new series
, edited by
H.
Ullmeier
(
Springer
,
Heidelberg
,
1975
), Vol. III/7b.
62.
R.
Wyckoff
,
Crystal Structures
, 2nd ed. (
Interscience
,
New York
,
1963
).
63.
R. J.
Zollweg
,
Phys. Rev.
100
,
671
(
1955
).
64.
C. H.
Rycroft
,
G. S.
Grest
,
J. W.
Landry
, and
M. Z.
Bazant
,
Phys. Rev. E
74
,
021306
(
2006
).
65.
C. H.
Rycroft
, “Multiscale modeling in granular flow,” Ph.D. dissertation (Massachusetts Institute of Technology,
2007
).
You do not currently have access to this content.