STEM Optical Sectioning for Imaging Screw Dislocations Core Structures\nin BCC Metals

0481153 - ÚFM 2019 RIV US eng J - Journal Article
Hernandez-Maldonado, D. - Yang, H. - Jones, L. - Gröger, Roman - Hirsch, P. B. - Ramasse, Q. M. - Nellist, P. D.
STEM Optical Sectioning for Imaging Screw Dislocations Core Structures
in BCC Metals.
Microscopy and Microanalysis. Roč. 22, S3 (2016), s. 1932-1933. ISSN 1431-9276. E-ISSN 1435-8115
R&D Projects: GA ČR(CZ) GA16-13797S
Institutional support: RVO:68081723
Keywords : screw dislocation * transmission electron microscopy * imaging
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 1.891, year: 2016

It is well known that the low-temperature plastic deformation of Body-Centred Cubic (BCC)
metals is controlled by the glide of 1/2[111] screw dislocations. Their low mobility is caused
by the delocalized nature of their cores which are extended into several planes in the zone
of the Burgers vector. This non-planar core spreading has been demonstrated by a number of
atomistic studies made in the last 46 years. However, attempts at experimental
observation have been hindered by the Eshelby twist effect. The aim of this work is to
investigate whether the edge and screw displacements associated with 1/2[111] screw
dislocations in BCC metals can be detected by optical sectioning in high-angle annular dark field
(HAADF) Scanning Transmission Electron Microscope (STEM) imaging conditions.
Permanent Link: http://hdl.handle.net/11104/0276778