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Evolution of mechanical response and dislocation microstructures in small-scale specimens under slightly different loading conditions

 
: Senger, J.; Weygand, D.; Motz, C.; Gumbsch, P.; Kraft, O.

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Preprint urn:nbn:de:0011-n-1251271 (1.1 MByte PDF)
MD5 Fingerprint: 4df6ad39d4ce1f9b10bb1a5ebc158fc2
Created on: 30.3.2012


The philosophical magazine 90 (2010), No.5, pp.617-628
ISSN: 1478-6435
ISSN: 0031-8086
ISSN: 1478-6443
English
Journal Article, Electronic Publication
Fraunhofer IWM ()
crystal plasticity; micropillar; deformation; simulation

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.

: http://publica.fraunhofer.de/documents/N-125127.html