Berlin 2015 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 42: Mechanical Properties I

MM 42.2: Talk

Wednesday, March 18, 2015, 16:00–16:15, TC 010

Absorption of dislocations in grain boundaries: atomic scale information for mesoscale models — •Julien Guénolé, Aruna Prakash, and Erik Bitzek — Department of Materials Science an Engineering, Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany

Dislocation-grain boundary (GB) interactions play an important role in the plastic deformation of polycrystalline materials, in particular for nanocrystalline metals. Advanced models for the mechanical behavior of nanocrystalline metals therefore need to take GBs explicitly into account. Several approaches to include GBs into mesoscale models (dislocation dynamics, strain gradient plasticity models, ...) were recently suggested. Such GB models need information, like the conditions for dislocation absorption, the change of dislocation stress fields after absorption, or on how much dislocation content can be absorbed. Atomistic simulations are uniquely positioned to provide such information and advance our understanding on dislocation-GB interactions.

Here we present results of carefully controlled studies of dislocations interacting with GBs in model bicrystalline samples. The mechanisms during dislocation-GB interaction are studied in quasi-2D and fully 3D samples. The stress and energetic signatures of the absorbed dislocations are analyzed and a novel approach to model the effect of the dislocation absorption on the dislocation stress field is proposed. A primary aim of the current study is to provide a better understanding of the role of absorbed dislocation content in the GB on the pinning and nucleation of other dislocations.