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Autor(en): Grabowski, Blazej
Zotov, Nikolay
Titel: Thermally-activated dislocation mobility in bcc metals : an accelerated molecular dynamics study
Erscheinungsdatum: 2021
Dokumentart: Zeitschriftenartikel
Seiten: 10
Erschienen in: Computational materials science 200 (2021), article 110804
URI: http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-ds-123182
http://elib.uni-stuttgart.de/handle/11682/12318
http://dx.doi.org/10.18419/opus-12301
ISSN: 0927-0256
Zusammenfassung: Plastic deformation in metals is controlled by dislocation density and mobility. In bcc metals the mobility of screw dislocations, which takes place by temperature- and stress-driven nucleation of critical kink-pairs, is most essential for deformation. However, the critical resolved shear stresses at low temperatures, as determined from molecular dynamics (MD) simulations performed at constant strain rate, are typically 2–3 times larger than the yield stresses measured experimentally. Here, an accelerated MD procedure is developed and employed to investigate the onset of dislocation mobility in the prototypical system bcc Nb. The method combines constant strain and temperature MD with hyperdynamics, using a bond-boost potential. We demonstrate, with a careful statistical analysis, that the method enables nucleation of critical kink-pairs and the determination of the Gibbs energy of kink-pair formation from accelerated MD simulations at experimentally-measured shear stresses.
Enthalten in den Sammlungen:03 Fakultät Chemie

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