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MM: Metall- und Materialphysik

MM 45: Mechanical Properties III

MM 45.1: Vortrag

Freitag, 31. März 2006, 12:30–12:45, IFW A

Intrinsic plastic deformation behaviour of the complex metallic alloy phase ß-Al-Mg — •Stefan Roitsch, Marc Heggen, Carsten Thomas, Marita Schmidt, and Michael Feuerbacher — Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany

We have performed macroscopic plastic deformation experiments on the complex metallic alloy ß-Al-Mg. This material is a technologically interesting lightweight alloy (density 2.2 g/cm3) with a face centred structure containing about 1168 atoms per unit cell. For the first time, the intrinsic plastic deformation behaviour of high-quality single crystalline material was characterized. Uniaxial deformation experiments at a constant strain rate of 10-4 s-1 were performed at temperatures between 225 and 375^∘C. It was found that the single crystalline ß-Al-Mg exhibits ductile behaviour down to temperatures of 225^∘C. At this temperature we find upper yield stresses of about 780 MPa. This is a very high value compared to other alloys in the Al-Mg system, for which yield stresses of the order of 300 MPa and below are found. The yield-point is followed by an almost constant flow-stress level up to strains of about 6%. Stress-relaxation tests and temperature changes were carried out in order to determine the thermodynamic activation parameters of the deformation process.