Berlin 2015 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 41: Electron Microscopy
MM 41.3: Talk
Wednesday, March 18, 2015, 16:15–16:30, TC 006
Comprehensive model of metadislocation motion in o-Al13Co4 — •Markus Heidelmann, Marc Heggen, Christian Dwyer, and Michael Feuerbacher — Ernst-Ruska-Centrum, Forschungszentrum Jülich, 52425 Jülich, Deutschland
In several complex metallic alloys plastic deformation is mediated by metadislocations. Due to the complex nature of these defects and the large number of atoms in their core region, little is known about the atomic rearrangements taking place during movement of a metadislocation. In this work we report on the first development of a fully three-dimensional model of a moving metadislocation including all atomic species. The CMA chosen for our study is the moderately complex o-Al13Co4, an orthorhombic phase with 102 atoms per unit cell. Using a combination of high-resolution scanning transmission electron microscopy and density functional theory, we have developed an atomic model for the [010] glide movement of a metadislocation in Al13Co4 extending to light elements and including the third dimension. Metadislocation movement was analysed employing a simulated-annealing procedure to minimize the total jump distance of all atoms within the model. While the distance of one glide step is 12.3 Å, the maximum jump distance of an individual atom is a much more moderate 3.4 Å. The approach described is versatile enough to be applied to other, more complex problems, for example metadislocation movement in є6-Al-Pd-Mn.
We kindly acknowledge funding from the DFG under project Pak 36 / FE 571/2-2.