Détail de la notice
Titre du Document
Examination of dislocations in ice
Three techniques have been used to study dislocations in ice: etch pitting-replication, transmission electron microscopy, and X-ray topography (XT). Each is considered, and it is shown that the most useful is XT. This is because ice has low absorption of X-rays and can be produced with a low dislocation density, thus, allowing relatively thick specimens to be studied. The many useful observations that have been made with conventional XT are presented. However, the introduction of high-intensity synchrotron radiation showed that conventional XT observations are of dislocations that have undergone recovery. Thus, the important dynamic observations and measurements that have been made using synchrotron XT are also outlined. In single crystals, it has been shown that slip mainly occurs by the movement of screw and 60° a/3(1120) dislocations on the basal plane. In addition, the operation of Frank-Read sources has been clearly demonstrated, and dislocation velocities have been measured. In contrast, in polycrystals, dislocation generation has been observed to occur at stress concentrations at grain boundaries, and this completely overwhelms any lattice dislocation generation mechanisms. The nature of faulted dislocation loops has been determined in both polycrystals and single crystals.
American Chemical Society
ISSN : 1528-7483
Crystal growth & design A. 2002, vol. 2, n° 2, pp. 127-134 [8 pages] [bibl. : 56 ref.]
Pour les membres de la communauté du CNRS, ce document est autorisé à la reproduction à titre gratuit.
Pour les membres des communautés hors CNRS, la reproduction de ce document à titre onéreux sera fournie sous réserve d’autorisation du Centre Français d’exploitation du droit de Copie.

Pour bénéficier de nos services (strictement destinés aux membres de la communauté CNRS (Centre National de la Recherche Scientifique), de l'ESR français (Enseignement Supérieur et Recherche), et du secteur public français & étranger) :