Berlin 2008 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 11: Nanostructured Materials III
MM 11.3: Vortrag
Montag, 25. Februar 2008, 15:15–15:30, H 0107
Strain rate sensitivity of ultrafine-grained Al and Al-Mg-alloys — •Andreas Böhner1, Johannes May1, Aferdita Vevecka-Priftaj2, Heinz Werner Höppel1, and Mathias Göken1 — 1Institute I: General Materials Properties, Department of Materials Science and Engineering, University of Erlangen-Nürnberg, Germany — 2Department of Physics, Polytechnic University of Tirana, Albania
Nanocrystalline or ultrafine-grained (UFG) metals are known to exhibit very high strength paired with high ductility. In this context, strain rate sensitivity (SRS) is regarded to be the main issue to explain this behaviour. Bulk UFG metals can be achieved by Equal Channel Angular Pressing (ECAP), where the material is deformed by repeated shear deformation. In this contribution, detailed investigations of the SRS of technically pure Al, AlMg and a technologically relevant Al-Mg-alloy (AA6061) were performed. For the precipitation hardenable AA6061-alloy a solution treated and a peak aged state were investigated. The SRS was determined by strain rate jump compression tests which were performed in a temperature range from room temperature (RT) up to 250 °C. It could be shown that an UFG microstructure significantly enhances the SRS, especially at elevated temperatures. The influences of precipitations, microstructure and number of ECAP passes on the SRS and the mechanical properties are also discussed.