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 Karl Franzens University Graz

Graz University of Technology 

Crystal plasticity as a mesoscopic theory of dislocations
Prof. Thomas Hochrainer
Institute of Strength of Materials, TU Graz
17:15 - 18:15 Tuesday 12 June 2018 TUG P2

Plastic deformation of crystals is mostly due to the motion of dislocations. Dislocations are line-like lattice defects, which may move when subject to stresses. Dislocations interact via long range stress fields. Because crystals possess very high densities of dislocations it seems a straight forward endeavor to develop a theory of crystal plasticity as a field theory of dislocations with methods from interacting particle physics.

However, there are various facts about dislocations which hinder a simple transfer of established methods in interacting particle physics to dislocation systems: due to the high energy of dislocations thermal effects are negligible (entropy plays no role), dislocations have restricted kinematics (non-ergodicity), and dislocations are flexible moving lines which may react and multiply (non-conservation).

In the current talk we review important progress which has been achieved during recent years towards a kinematical and energetical descriptions of evolving dislocation systems. This progress has led to the first mesoscopic field theory for curved dislocations under restricted deformation conditions. We shall also discuss further challenges which have yet to be overcome for a more general continuum theory of dislocations.