Dresden 2014 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 41: Computational Materials Modelling VI - Dislocations

MM 41.5: Talk

Wednesday, April 2, 2014, 12:30–12:45, IFW D

Dislocation – grain boundary interactions in aluminum: insights from atomistic simulations on bi-crystalline and nanocrystalline samples — •Julien Guénolé, Aruna Prakash, and Erik Bitzek — Department of Materials Science and Engineering, Institute I: General Materials Properties, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany

The interactions between dislocations and grain boundaries (GB) are a dominating factor in the plasticity of nanocrystalline metals. Atomistic simulations have played a key role in improving our understanding of the atomic scale processes that govern dislocation–GB interactions. However, most studies so far have been performed on either quasi-2D bicrystal set-ups with straight dislocation lines or on unrealistic nanocrystalline samples generated by Voronoi tessaltation. In both cases, the dislocations interact with planar GBs.

Here, we present results of controlled studies on dislocations interacting with GBs in model bi-crystalline samples as well as in more realistic nanocrystalline samples. The deposition process of curved dislocations is compared to the absorption of straight dislocations in a quasi-2D set-up. In addition, the stress-signature of the absorbed dislocation is analyzed. The results are compared with the absorption and pinning of dislocations at curved and planar GBs in nanocrystalline samples with controlled GB network topology. 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.