Evolution of mechanical response and dislocation microstructures in small-scale specimens under slightly different loading conditions |
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Authors: | Jochen Senger Daniel Weygand Christian Motz Peter Gumbsch Oliver Kraft |
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Institution: | 1. IZBS, Universit?t Karlsruhe (TH) , Kaiserstr. 12, 76131 Karlsruhe, Germany jochen.senger@kit.edu;3. IZBS, Universit?t Karlsruhe (TH) , Kaiserstr. 12, 76131 Karlsruhe, Germany;4. IZBS, Universit?t Karlsruhe (TH) , Kaiserstr. 12, 76131 Karlsruhe, Germany;5. Erich Schmid Institute, Austrian Academy of Sciences , Jahnstr. 12, 8700 Leoben, Austria;6. IWM, Fraunhofer Institut für Werkstoffmechanik , W?hlerstr. 11, 79108 Freiburg, Germany;7. Institut für Materialforschung II (IMF II) , Forschungszentrum Karlsruhe, Germany |
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Abstract: | In small dimensions, the flow stress of metallic samples shows a size-dependence such that smaller is stronger, even in nominally strain gradient-free loading conditions. However, the role of the boundary conditions in miniaturised tension or compression tests on the mechanical response and dislocation structure has not been studied in detail. In simulations performed with a three-dimensional discrete dislocation dynamics tool, initial, well-defined dislocation microstructures are loaded in tension with different boundary conditions including superimposed torsion moments. The influence of the loading conditions on details of the evolving dislocation microstructure was investigated by using identical starting configuration. An additional torsion moment significantly influences the dislocation activity since forest-dislocations are generated, but size effect of the flow stress is found to be unchanged. |
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Keywords: | dislocation structures micro samples simulation boundary conditions dislocation dynamics |
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