Dresden 2009 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 35: Poster Session II

MM 35.32: Poster

Wednesday, March 25, 2009, 16:30–18:30, P4

Creep measurements on high pressure torsion treated materials — •Jörn Leuthold, Harald Rösner, and Gerhard Wilde — Universität Münster, Institut für Materialphysik, 48149 Münster, Germany

In ultrafine grained and in nanocrystalline materials the small grain size and the presence of defects with high specific excess energy densities lead to modifications of the basic mechanisms that can accommodate externally applied mechanical stresses. Additionally, for plasic deformation, grain boundary controlled mechanisms, such as grain boundary (GB) emitted dislocations and partial dislocations, twinning, GB diffusion and sliding can be more important or even dominant. To study the modified deformation behaviour several copper samples were prepared by high pressure torsion (HPT), a technique to induce high shear stresses on a specimen to produce fine grained or even nanocrystalline material. A device for creep measurements was built to perform tensile stress-strain-rate tests at room temperature for the measurement of strain-rate sensitivity of the HPT samples. The results are discussed with respect to the modified plasticity mechanisms in ultrafine and in nanocrystalline metals.