Dresden 2006 – wissenschaftliches Programm
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MM: Metall- und Materialphysik
MM 17: Symposium Severe Plastic Deformation IV
MM 17.6: Fachvortrag
Dienstag, 28. März 2006, 17:00–17:30, IFW A
Dilatometric studies on ECAP deformed Cu — •Kai Klement and Ferdinand Haider — University of Augsburg
By means of dilatometric measurements the excess volume of lattice defects in severely deformed Cu samples was investigated, in order to determine the type and concentration of these defects. Anisotropic behaviour and inhomogeneities where discovered.
High purity Cu (99.99%) was deformed by equal channel angular pressing for up to eight passes at room temperature, using 120∘ tooling, by either route A or BC, generating high concentrations of non equilibrium defects. Annealing experiments with constant heat rate revealed shrinking of the samples in the order of 10−4 at temperatures between 180∘C and 250∘C, depending on the degree of deformation. The temperature characteristics of the annealing process did not provide any further information about different types of defects, showing only one sharp step in the dilatometer signal, which is in accordance with DSC, TEM and XRD investigations. Measurements along the three orthogonal directions of the die outlet channel showed significant differences in shrinking behaviour, indicating the annealing of anisotropic defect configurations like vacancy and dislocation agglomerates. In order to identify the nature of these defects, moleculardynamic simulations are planned, which provide the volumes of typical defect configurations.