Dislocation‐Mediated Hydride Precipitation in Zirconium

The formation of hydrides challenges the integrity of zirconium (Zr) fuel cladding in nuclear reactors. The dynamics of hydride precipitation are complex. Especially, the formation of the butterfly or bird‐nest configurations of dislocation structures around hydride is rather intriguing. By in‐situ...

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Bibliographic Details
Published in:Small (Weinheim an der Bergstrasse, Germany) Germany), 2022-03, Vol.18 (9), p.e2105881-n/a
Main Authors: Liu, Si‐Mian, Ishii, Akio, Mi, Shao‐Bo, Ogata, Shigenobu, Li, Ju, Han, Wei‐Zhong
Format: Article
Language:English
Subjects:
Chemical precipitation
Configurations
Density functional theory
dislocation
Hydrides
Nanotechnology
Nuclear fuel elements
Nuclear fuels
Nuclear reactors
precipitation
Solubility
stress
Stress distribution
Tensile stress
Zirconium
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Summary:The formation of hydrides challenges the integrity of zirconium (Zr) fuel cladding in nuclear reactors. The dynamics of hydride precipitation are complex. Especially, the formation of the butterfly or bird‐nest configurations of dislocation structures around hydride is rather intriguing. By in‐situ transmission electron microscopy experiments and density functional theory simulations, it is discovered that hydride growth is a hybrid displacive‐diffusive process, which is regulated by intermittent dislocation emissions. A strong tensile stress field around the hydride tip increases the solubility of hydrogen in Zr matrix, which prevents hydride growth. Punching‐out dislocations reduces the tensile stress surrounding the hydride, decreases hydrogen solubility, reboots the hydride precipitation and accelerates the growth of the hydride. The emission of dislocations mediates hydride growth, and finally, the consecutively emitted dislocations evolve into a butterfly or bird‐nest configuration around the hydride. It is discovered that hydride growth is a hybrid displacive‐diffusive process, which is regulated by intermittent dislocation emissions. A strong tensile stress field around the hydride tip increases the solubility of hydrogen in the Zr matrix, which prevents hydride growth. Punching‐out dislocations reduces the tensile stress field, decreases hydrogen solubility, reboots hydride precipitation, and accelerates hydride growth.
ISSN:1613-6810
1613-6829
DOI:10.1002/smll.202105881