Regensburg 2013 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 37: Mechanical Properties I

MM 37.4: Talk

Wednesday, March 13, 2013, 12:30–12:45, H26

Homogeneity and time dependent behavior of high pressure torsion processed copper — •Jörn Leuthold, Matthias Wegner, Sergiy Divinski, Martin Peterlechner, and Gerhard Wilde — Institute of Materials Physics, University of Muenster, 48149 Münster, Germany

The presence of a high defect density in the form of dislocation networks and high and low angle grain boundaries affects the plastic behavior of materials processed by severe plastic deformation . With a decrease of grain size into the sub-micrometer range, dislocation-grain boundary interactions are of increased significance for the accommodation of externally applied stresses. For this study several samples were produced by high pressure torsion, where, under a hydrostatic pressure of several GPa, large shear strains can be employed by a rotating die. Characteristic for this process is a non uniform plastic flow, since shear strain and velocity depend on the distance from the axis of rotation. As a result, an inhomogeneous microstructure is produced. After preparation, the samples were tested by nanoindentation, where, in addition to the hardness, the time dependent properties were analyzed by implementing a holding phase of 300 sec at the maximum load. Electron back-scatter diffraction was used to link the observed features of the microstructure to the results of the nanoindentation measurements.