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Repulsion leads to coupled dislocation motion and extended work hardening in bcc metals

Srivastava, K.; Weygand, D.; Caillard, D.; Gumbsch, P.

Work hardening in bcc single crystals at low homologous temperature shows a strong orientation-dependent hardening for high symmetry loading, which is not captured by classical dislocation density based models. We demonstrate here that the high activation barrier for screw dislocation glide motion in tungsten results in repulsive interactions between screw dislocations, and triggers dislocation motion at applied loading conditions where it is not expected. In situ transmission electron microscopy and atomistically informed discrete dislocation dynamics simulations confirm coupled dislocation motion and vanishing obstacle strength for repulsive screw dislocations, compatible with the kink pair mechanism of dislocation motion in the thermally activated (low temperature) regime. We implement this additional contribution to plastic strain in a modified crystal plasticity framework and show that it can explain the extended work hardening regime observed for [100] oriented tungsten single crystal. This may contribute to better understanding the increase in ductility of highly deformed bcc metals.

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Verlagsausgabe §
DOI: 10.5445/IR/1000124413
Veröffentlicht am 09.10.2020
DOI: 10.1038/s41467-020-18774-1
Zitationen: 4
Zitationen: 5
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Materialien - Computational Materials Science (IAM-CMS)
Publikationstyp Zeitschriftenaufsatz
Publikationsdatum 09.10.2020
Sprache Englisch
Identifikator ISSN: 2041-1723
KITopen-ID: 1000124413
Erschienen in Nature Communications
Verlag Elsevier
Band 11
Heft 1
Seiten Art. Nr.: 5098
Nachgewiesen in Web of Science
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