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M: Metallphysik

M 23: Mechanische Eigenschaften IV

M 23.3: Vortrag

Dienstag, 25. März 2003, 17:00–17:15, IFW B

Computer simulations on the effects of the obstacle extension on particle strengthening — •Volker Mohles — Institut für Materialphysik, Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster

In particle strengthening, if the length scales are normalized to the obstacle density in the glide plane, the main obstacle parameter is the maximum obstacle force in relation to the line tension. This force can be assigned to a point obstacle and used for analytical theories to calculate the critical resolved shear stress. But these are valid only for very low particle volume fractions. In the literature, the effects of a finite obstacle extension have been investigated by considering a finite obstacle extension in the direction either normal (Mott, Nabarro, Schwarz, Labusch) or parallel (Ham) to the dislocation line. In the present contribution both extensions are considered concurrently in dislocation dynamics simulations. Two simulation approaches are compared: one makes use of the line tension model, and the other one replaces this simple model by the dislocation self-interaction concept of Brown and Bacon. The direct comparison of these models allows to derive an effective line tension for particle strengthening.