Dynamics of coarse grained dislocation densities from an effective free energy

I. Groma, G. Györgyi, B. Kocsis

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

A continuum description of the time evolution of an ensemble of parallel straight dislocations has recently been derived from the equations of motion of individual dislocations. The predictions of the continuum model were compared to the results of discrete dislocation dynamics (DDD) simulations for several different boundary conditions. It was found that it is able to reproduce all the features of the dislocation ensembles obtained by DDD simulations. The continuum model, however, is systematically established only for single slip. Due to the complicated structure of the equations extending the derivation procedure for multiple slip is not straightforward. In this paper an alternative approach based on a thermodynamics-like principle is proposed to derive continuum equations for single slip. An effective free energy is introduced even for zero physical temperature, which yields equilibrium conditions giving rise to Debye-like screening; furthermore, it generates dynamical equations along the lines of phase field theory. It is shown that this leads essentially to the same evolution equations as obtained earlier. In addition, it seems that this framework is extendable to multiple slip as well.

Original languageEnglish
Pages (from-to)1185-1199
Number of pages15
JournalPhilosophical Magazine
Volume87
Issue number8-9
DOIs
Publication statusPublished - Mar 2007

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free energy
slip
continuums
equations of motion
screening
derivation
simulation
Equations
Energy
Dislocation
boundary conditions
thermodynamics
Slip
predictions
temperature
Simulation
Ensemble
Dislocation Dynamics

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Dynamics of coarse grained dislocation densities from an effective free energy. / Groma, I.; Györgyi, G.; Kocsis, B.

In: Philosophical Magazine, Vol. 87, No. 8-9, 03.2007, p. 1185-1199.

Research output: Contribution to journalArticle

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