Regensburg 2010 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 21: Mechanical Properties I

MM 21.3: Talk

Tuesday, March 23, 2010, 10:45–11:00, H6

Dislocations in the Complex Metallic Alloy T-Al-Mn-Pd — •Marc Heggen, Lothar Houben, and Michael Feuerbacher — Institut für Festkoerperforschung, Forschungszentrum Juelich GmbH, D-52425 Juelich, Germany

The deformation mechanisms of complex metallic alloys - crystalline solids containing up to thousands of atoms per unit cell - are widely unknown. Due to the large lattice parameters of these materials, conventional dislocation mechanisms are prone to failure. We investigated the complex metallic alloy T-Al-Mn-Pd with 156 atoms per unit cell using aberration-corrected high-resolution transmission electron microscopy. We found a highly complex deformation mechanism, based on the movement of a dislocation core mediating strain and separate escort defects. Upon deformation, the escort defects move along with the dislocation core and locally transform the material structure. This mechanism implies the coordinated movement of hundreds of atoms per elementary glide step. Nevertheless it can be described by simple rearrangement of basic structural subunits.