Crystal Plasticity Treated as a Quasi-Static Material Flow through Adjustable Crystal Lattice
J. Kratochvíl
Czech Technical University, Department of Physics, Faculty of Civil Engineering, Thákurova 7, 166 29 Prague, and Faculty of Mathematics and Physics, Mathematical Institute, Charles University, Sokolovská 83, 186 75 Prague, Czech Republic
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Considering high pressure torsion experiments as a motivation, plastic behavior of crystalline solids is treated as a highly viscous material flow through an adjustable crystal lattice. Instead of the traditional decomposition rule considering the deformation gradient as a product of the elastic and plastic parts, the proposed model is based on its rate form: the velocity gradient consists of the lattice velocity gradient and the sum of the velocity gradients corresponding to the slip rates of individual slip systems; The slip strains themselves are not defined in the model. The geometrical changes caused by material flow and the slip strains can be specified a posteriori. Crystal lattice distortions are measured with respect to a lattice reference configuration. In an adopted rigid plastic approximation the lattice distortions are reduced to rotations. Constitutive equations incorporate non-local hardening caused by close range interactions among dislocations.
DOI: 10.12693/APhysPolA.122.482
PACS numbers: 62.20.F-, 81.40.Lm, 83.50.-v