Dresden 2006 – scientific programme
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MM: Metall- und Materialphysik
MM 3: Symposium Modern Metallic Materials Design I
MM 3.7: Talk
Monday, March 27, 2006, 12:15–12:30, IFW B
The complex metallic alloy phase Al13Co4: Plastic deformation properties and defects — •Marc Heggen1, Dewei Deng1,2, Michael Feuerbacher1, Ze Zhang2, and Ke Hsin Kuo2 — 1Institut fuer Festkoerperforschung, Forschungszentrum Juelich GmbH, D-52425 Juelich — 2Beijing Laboratory of Electron Microscopy, Chinese Academy of Sciences, Beijing, People’s Republic of China
Plastic deformation experiments were performed on single crystals of the orthorhombic Al13Co4 complex metallic alloy phase in a temperature range between 600 and 800 ∘C. The stress-strain curves show a pronounced yield-drop effect followed by a regime of weak work hardening. Incremental experiments like stress-relaxation tests and temperature changes are conducted in order to determine thermodynamic activation parameters of the deformation process.
Microstructural investigations by means of transmission electron microscopy reveals that dislocation motion on (0 0 1) planes is the basic mechanism of plastic deformation in Al13Co4. Dislocation cores and attached planar defects were investigated by lattice fringe imaging and interpreted in terms of a tiling model. The planar defects are thin shear zones involving a phase transformation from the orthorhombic to a structurally closely related monoclinic phase. The dislocations cores are closely related to those of the metadislocations recently suggested by Feuerbacher and Heggen (Phil. Mag., 2005, in press) and possess the same Burgers vector of 2.9 Å.