Berlin 2015 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 41: Electron Microscopy

MM 41.1: Vortrag

Mittwoch, 18. März 2015, 15:45–16:00, TC 006

Five-fold dissociation of dislocations in the hexagonal complex metallic alloy my-AlMn — •Marc Heggen, Stefan Roitsch, and Michael Feuerbacher — Ernst Ruska Centrum, Forschungszentrum Juelich GmbH, 52425 Juelich, Germany

Complex metallic alloys (CMAs) are a class of intermetallics characterized by a high structural complexity, large lattice parameters, and a multitude of atoms per unit cells. In recent years, novel complex defects and new mechanisms of plastic deformation have been reported in these alloys. In this contribution defects in the CMA my-AlMn, a hexagonal phase (space group P63/mmc) with 563 atoms per unit cell and lattice parameters a=2.0 nm and c=2.5 nm are investigated. Using state-of-the-art aberration-corrected scanning transmission electron microscopy, the atomic dislocation and stacking fault structure is studied in plastically deformed my-phase samples. We demonstrate the existence of groups of five dissociated dislocations, having [0 0 1] line direction. The dislocations are partials connected by complex stacking faults with typical overall splitting distance of 100 nm employing two different types of hexagonal structural subunits.