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Site occupancy of interstitial deuterium atoms in face-centred cubic iron

Authors :
Toyoto Sato
Riko Iizuka
Hiroyuki Saitoh
Asami Sano-Furukawa
Shin Ichi Orimo
Akihiko Machida
Takanori Hattori
Motoaki Matsuo
Hidehiko Sugimoto
Naruki Endo
Katsutoshi Aoki
Yoshinori Katayama
Source :
Nature Communications
Publication Year :
2014
Publisher :
Springer Science and Business Media LLC, 2014.

Abstract

Hydrogen composition and occupation state provide basic information for understanding various properties of the metal–hydrogen system, ranging from microscopic properties such as hydrogen diffusion to macroscopic properties such as phase stability. Here the deuterization process of face-centred cubic Fe to form solid-solution face-centred cubic FeDx is investigated using in situ neutron diffraction at high temperature and pressure. In a completely deuterized specimen at 988 K and 6.3 GPa, deuterium atoms occupy octahedral and tetrahedral interstitial sites with an occupancy of 0.532(9) and 0.056(5), respectively, giving a deuterium composition x of 0.64(1). During deuterization, the metal lattice expands approximately linearly with deuterium composition at a rate of 2.21 Å3 per deuterium atom. The minor occupation of the tetrahedral site is thermally driven by the intersite movement of deuterium atoms along the ‹111› direction in the face-centred cubic metal lattice.<br />Knowledge of hydrogen content and coordination in deuterized metals is of importance. Here, the authors study the deuterization of face-centred cubic iron in-situ via neutron diffraction, observing the occupation by hydrogen of both octahedral and tetrahedral interstitial sites.

Details

ISSN :
20411723
Volume :
5
Database :
OpenAIRE
Journal :
Nature Communications
Accession number :
edsair.doi.dedup.....67b112746172500ccca3e92414aa2266
Full Text :
https://doi.org/10.1038/ncomms6063