Three-dimensional scanning transmission electron microscopy of dislocation loops in tungsten.

Détails

ID Serval
serval:BIB_804ABD450075
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Three-dimensional scanning transmission electron microscopy of dislocation loops in tungsten.
Périodique
Micron
Auteur(s)
Hasanzadeh S., Schäublin R., Décamps B., Rousson V., Autissier E., Barthe M.F., Hébert C.
ISSN
1878-4291 (Electronic)
ISSN-L
0968-4328
Statut éditorial
Publié
Date de publication
10/2018
Peer-reviewed
Oui
Volume
113
Pages
24-33
Langue
anglais
Notes
Publication types: Journal Article
Publication Status: ppublish
Résumé
Scanning transmission electron microscopy (STEM) imaging using diffraction contrast is a powerful technique to assess crystal defects. In this work it is used to assess the spatial distribution of radiation induced defect in tungsten. In effect, its irradiation leads to the formation of nanometric dislocation loops that under certain conditions may form intriguing 3-D rafts. In this study, we have irradiated thin tungsten samples in situ in a TEM with 1.2 MeV W ions to 0.017 dpa at room temperature (RT) and at 700 °C. Besides the Burgers vector analysis, the number density and size of the dislocation loops with their spatial arrangement were quantitatively characterized by stereo imaging in STEM mode. Most of the loops have a Burgers vector ½ a <sub>0</sub> 〈111〉, with some a <sub>0</sub> 〈100〉 at room temperature. Loops are located mainly in the simulated damage profile but there is also a significant portion in deeper regions of the sample, indicating that loops in W diffuse easily, even at RT. At 700 °C, loops form elongated rafts that contain dislocation segments having a Burgers vector ½ a <sub>0</sub> 〈111〉. The rafts are narrow and reside on {111} planes; they are elongated along 〈110〉 directions, which correspond, when combined to the rafts' Burgers vector, to the lines of edge dislocations. Compared to conventional TEM, 3-D analysis in STEM appears thus as a powerful technique for quantitative analyses of defects in tungsten, as it allows reducing the background diffraction contrast and reaching thicker areas of the electron transparent foil, here 0.5 μm of tungsten at 200 kV.
Mots-clé
Dislocation, Metallurgy, STEM, Stereo-imaging
Pubmed
Web of science
Création de la notice
29/06/2018 17:01
Dernière modification de la notice
20/08/2019 15:40
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