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Influence of hydrogen on the stability of iron phases under pressure
Author(s) -
Skorodumova N. V.,
Ahuja R.,
Johansson B.
Publication year - 2004
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl019736
Subject(s) - hydrogen , materials science , hydride , impurity , crystallography , thermodynamics , chemistry , metallurgy , metal , physics , organic chemistry
The influence of hydrogen presence on the stability of iron phases (bcc, hcp, dhcp, fcc, simple cubic) in a wide pressure interval at 0 K has been studied by the first‐principles projector augmented‐wave (PAW) method. Hydrogen is shown to occupy different interstitial lattice positions depending on the type of structure and pressure. An introduction of hydrogen impurities (∼6 at. %) leads to a stabilization of the close‐packed iron structures, shifting the calculated pressure of the bcc‐hcp transition from ∼9 GPa for pure iron to 7 GPa for Fe (6 at. % H). This tendency is further enhanced in the iron hydride structures. The iron hydrides in the close‐packed structures (hcp, dhcp, fcc) are essentially degenerate in energy and found to be most stable in the whole pressure range.