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Elucidating the dual role of grain boundaries as dislocation sources and obstacles and its impact on toughness and brittle-to-ductile transition

Reiser, Jens 1; Hartmaier, Alexander
1 Karlsruher Institut für Technologie (KIT)

Abstract (englisch):

In this paper, we resolve the role of grain boundaries on toughness and the brittle-to-ductile transition. On the one hand, grain boundaries are obstacles for dislocation glide. On the other hand, the intersection points of grain boundaries with the crack front are assumed to be preferred dislocation nucleation sites. Here, we will show that the single contributions of grain boundaries (obstacles vs. source) on toughness and the brittle-to-ductile transition are contradicting, and we will weight the single contributions by performing carefully designed numerical experiments by means of two-dimensional discrete dislocation dynamics modelling. In our parameter studies, we vary the following parameters: (i) the mean free path for dislocation glide, δ, combined with (ii) the (obstacle) force of the grain boundary, ϕ, and (iii) the dislocation source spacing along the crack front, λ. Our results show that for materials or microstructures for which the mean distance of the intersection points of grain boundaries with the crack front is the relevant measure for λ, a decrease of grain size results in an increase of toughness. The positive impact of grain boundaries outweighs the negative consequences of dislocation blocking. ... mehr

Verlagsausgabe §
DOI: 10.5445/IR/1000126069
Veröffentlicht am 12.11.2020
DOI: 10.1038/s41598-020-59405-5
Zitationen: 17
Web of Science
Zitationen: 15
Zitationen: 22
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Materialien – Angewandte Werkstoffphysik (IAM-AWP)
Publikationstyp Zeitschriftenaufsatz
Publikationsdatum 17.02.2020
Sprache Englisch
Identifikator ISSN: 2045-2322
KITopen-ID: 1000126069
HGF-Programm 31.03.09 (POF III, LK 01) Strukturmaterial f. Blanket und Divertor
Erschienen in Scientific reports
Verlag Nature Research
Band 10
Heft 1
Seiten Art.-Nr.: 2739
Nachgewiesen in Web of Science
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