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Effect of Eshelby twist on core structure of screw dislocations in molybdenum: atomic structure and electron microscope image simulations
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SYSNO ASEP 0359531 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Effect of Eshelby twist on core structure of screw dislocations in molybdenum: atomic structure and electron microscope image simulations Author(s) Gröger, Roman (UFM-A) RID, ORCID
Dudeck, K. J. (CA)
Nellist, P. D. (GB)
Vitek, V. (US)
Hirsch, P. B. (GB)
Cockayne, D. J. H. (GB)Number of authors 6 Source Title Philosophical Magazine. - : Taylor & Francis - ISSN 1478-6435
Roč. 91, č. 18 (2011), s. 2364-2381Number of pages 18 s. Language eng - English Country GB - United Kingdom Keywords screw dislocation ; thin foil ; Eshelby twist ; free surface ; HREM Subject RIV BM - Solid Matter Physics ; Magnetism R&D Projects GAP204/10/0255 GA ČR - Czech Science Foundation (CSF) CEZ AV0Z20410507 - UFM-A (2005-2011) UT WOS 000290669500005 DOI 10.1080/14786435.2011.562474 Annotation This paper addresses the question as to whether the core structure of screw dislocations in Mo in the bulk can be obtained from high-resolution electron microscopy (HREM) images of such dislocations viewed end-on in a thin foil. Atomistic simulations of the core structure of screw dislocations in elastically anisotropic Mo were carried out using bond order potentials. They show that the differential displacements of the atoms at the surface are different with components perpendicular to the Burgers vector about five times larger than those in the middle of the foil, the latter being characteristic of the bulk. Nye tensor plots show that the surface relaxation stresses strongly affect the incompatible distortions. HREM simulations of the computed structure reflect the displacements at the exit surface, modified by interband scattering and the microscope transfer function. Nye tensor plots obtained from the HREM images show that interband scattering also affects the incompatible distortions. It is concluded that it would be difficult to obtain the core structure of screw dislocations in the bulk Mo from HREM images, even under ideal experimental conditions. Workplace Institute of Physics of Materials Contact Yvonna Šrámková, sramkova@ipm.cz, Tel.: 532 290 485 Year of Publishing 2012
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