Berlin 2005 – scientific programme
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M: Metallphysik
M 11: Symposium Complex Metallic Alloys III
M 11.5: Talk
Friday, March 4, 2005, 18:30–18:45, TU H1058
Plastic deformation behaviour of Al13Co4 single crystals — •Marc Heggen, Dewei Deng, and Michael Feuerbacher — Institut für Festkörperforschung Forschungszentrum Jülich GmbH,
par 52425 Jülich, Germany
Al13Co4 is an orthorhombic phase with lattice parameters a = 0.82 nm, b = 1.24 nm, and c = 1.45 nm. It is a structurally complex alloy phase with 101 atoms per unit cell. The structural key feature of this material are pair-connected pentagonal prismatic channels along the b direction. Around these, the structure can be matched by alternatingly oriented flattened hexagons . Al13Co4 is a particularly interesting phase due to its structural relationship to ξ ’-Al-Pd-Mn, in which the Metadislocation-mediated deformation process was discovered.
We have performed uniaxial deformation tests in compression on Al13Co4 single crystals, which were grown by means of the Bridgman technique. The material was deformed in a temperature range between 650 and 900 ∘C at strain rates of 10−5 and 10−4 s−1. It shows pronounced yielding and continuous hardening after the lower yield point. Stress-relaxation tests, strain-rate changes and temperature-cycling tests were performed in order to determine thermodynamic activation parameters. The deformed samples show a number of slip lines on the surface oriented 45∘ with respect to the compression direction.