Intermittent dislocation density fluctuations in crystal plasticity from a phase-field crystal model

TY - JOUR

T1 - Intermittent dislocation density fluctuations in crystal plasticity from a phase-field crystal model

AU - Tarp, Jens M.

AU - Angheluta, Luiza

AU - Mathiesen, Joachim

AU - Goldenfeld, Nigel

PY - 2014/12/31

Y1 - 2014/12/31

N2 - Plastic deformation mediated by collective dislocation dynamics is investigated in the two-dimensional phase-field crystal model of sheared single crystals. We find that intermittent fluctuations in the dislocation population number accompany bursts in the plastic strain-rate fluctuations. Dislocation number fluctuations exhibit a power-law spectral density 1/f2 at high frequencies f. The probability distribution of number fluctuations becomes bimodal at low driving rates corresponding to a scenario where low density of defects alternates at irregular times with high populations of defects. We propose a simple stochastic model of dislocation reaction kinetics that is able to capture these statistical properties of the dislocation density fluctuations as a function of shear rate.

AB - Plastic deformation mediated by collective dislocation dynamics is investigated in the two-dimensional phase-field crystal model of sheared single crystals. We find that intermittent fluctuations in the dislocation population number accompany bursts in the plastic strain-rate fluctuations. Dislocation number fluctuations exhibit a power-law spectral density 1/f2 at high frequencies f. The probability distribution of number fluctuations becomes bimodal at low driving rates corresponding to a scenario where low density of defects alternates at irregular times with high populations of defects. We propose a simple stochastic model of dislocation reaction kinetics that is able to capture these statistical properties of the dislocation density fluctuations as a function of shear rate.

U2 - 10.1103/PhysRevLett.113.265503

DO - 10.1103/PhysRevLett.113.265503

M3 - Journal article

C2 - 25615353

AN - SCOPUS:84920288202

SN - 0031-9007

VL - 113

JO - Physical Review Letters

JF - Physical Review Letters

IS - 26

M1 - 265503

ER -