Dislocation dynamics and crystal plasticity in the phase-field crystal model

Audun Skaugen, Luiza Angheluta, Jorge Vinals

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

A phase-field model of a crystalline material is introduced to develop the necessary theoretical framework to study plastic flow due to dislocation motion. We first obtain the elastic stress from the phase-field crystal free energy under weak distortion and show that it obeys the stress-strain relation of linear elasticity. We focus next on dislocations in a two-dimensional hexagonal lattice. They are composite topological defects in the weakly nonlinear amplitude equation expansion of the phase field, with topological charges given by the standard Burgers vector. This allows us to introduce a formal relation between the dislocation velocity and the evolution of the slowly varying amplitudes of the phase field. Standard dissipative dynamics of the phase-field crystal model is shown to determine the velocity of the dislocations. When the amplitude expansion is valid and under additional simplifications, we find that the dislocation velocity is determined by the Peach-Koehler force. As an application, we compute the defect velocity for a dislocation dipole in two setups, pure glide and pure climb, and compare it with the analytical predictions.

Original languageEnglish (US)
Article number054113
JournalPhysical Review B
Volume97
Issue number5
DOIs
StatePublished - Feb 26 2018

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Dislocations (crystals)
plastic properties
crystal field theory
Plasticity
Crystals
crystals
Burgers vector
Defects
Plastic flow
Free energy
Elasticity
expansion
plastic flow
defects
Crystalline materials
simplification
Composite materials
elastic properties
free energy
dipoles

Cite this

Dislocation dynamics and crystal plasticity in the phase-field crystal model. / Skaugen, Audun; Angheluta, Luiza; Vinals, Jorge.

In: Physical Review B, Vol. 97, No. 5, 054113, 26.02.2018.

Research output: Contribution to journalArticle

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