Intermittent dislocation density fluctuations in crystal plasticity from a phase-field crystal model
Abstract
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 at high frequencies . The probability distribution of number fluctuations becomes bimodal at low driving rates corresponding to a scenario where low density of defects alternate at irregular times with high population 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.
Cite
@article{arxiv.1412.8653,
title = {Intermittent dislocation density fluctuations in crystal plasticity from a phase-field crystal model},
author = {Jens M. Tarp and Luiza Angheluta and Joachim Mathiesen and Nigel Goldenfeld},
journal= {arXiv preprint arXiv:1412.8653},
year = {2015}
}