Dresden 2011 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 12: Postersitzung I

MM 12.30: Poster

Montag, 14. März 2011, 17:30–19:00, P5

Efficient ab-initio characterisation of the parameter space of grain boundaries — Naveed Ahmed, Xueyong Pang, Christian Kellermann, •Rebecca Janisch, Holger Dette, and Alexander Hartmaier — ICAMS, Ruhr-Universität Bochum, Germany

A grain boundary is characterised by at least five macroscopic and three microscopic degrees of freedom, the orientation of the grain boundary plane, the misorientation axis and the misorientation angle, as well as the interface translation state. At the same time, continuum modeling of polycrystals requires knowledge of the elastic and plastic properties of all kind of interfaces in their microstructure. To capture the physics of grain boundary sliding, migration and decohesion, these processes should be investigated by atomistic calculations. Especially if the influence of segregated impurities, which can alter the bond character, shall also be described, a quantum mechanical treatment is necessary. However, sampling the above mentioned parameter space ab initio remains a formidable task, even with today's computers. In this paper we will introduce our investigation of the mechanical properties of grain boundaries in aluminum, which aims at replacing such a comprehensive sampling by as few representative calculations as possible. For this we are evaluating a "design of experiment scheme" combined with insight on the role of crystallography that we gain from our ab-initio calculations: On the one hand we are investigating discriminating features in the elastic and plastic response of tilt and twist grain boundaries. On the other hand we are looking for common behaviour that enables a unified treatment and a separation of variables.