Regensburg 2007 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 6: Interfaces II

MM 6.4: Vortrag

Montag, 26. März 2007, 12:30–12:45, H6

Ab-initio based multiscale analysis of the 5D configurational space of Grain Boundaries in Aluminum. — •Liverios Lymperakis and Jörg Neugebauer — Computational Materials Design department, Max-Planck-Institut für Eisenforschung, Düsseldorf

A rapidly evolving approach in materials design is Grain Boundary (GB) engineering, i.e. optimizing the population of GBs with desirable geometry by suitable thermomechanical treatment. To achieve this, a deeper understanding and quantification of the interplay between the GB energies with respect to the misorientation of the two grains (3 dimensional configuration space) and the inclination of the boundary plane (2D space) are crucial. In this work we combine first principles density functional theory with modified embedded atom method (MEAM) calculations in order to explore the 5D-phase space of GBs in Aluminum. To handle this problem, we have generalized our implicit boundary multiscale schema (IBMS) which had been originally developed and applied to study isolated dislocations [1]. In a first step we have explored the three degrees of freedom required to describe the misorientation of the two grains: as an example we discuss symmetrical tilt GBs having the rotational axis along high symmetry directions of the fcc lattice. As a second example we focus on the low energy misorientation angles and explore the remaining two degrees of freedom associated with the inclination of the boundary plane. These results have been able to interpret and explain recent experimental data on GB occupation [2]. [1] L. Lymperakis et al. Phys. Rev. Lett. 93, 196401 (2004). [2] C.-S. Kim et al. Scripta Materialia 54, 1005 (2006).