Breakdown of avalanche critical behaviour in polycrystalline plasticity - Archive ouverte HAL Access content directly
Journal Articles Nature Materials Year : 2005

Breakdown of avalanche critical behaviour in polycrystalline plasticity

(1) , (1) , (1)
1

Abstract

Acoustic emission experiments on creeping ice as well as numerical simulations argue for a self-organization of collective dislocation dynamics during plastic deformation of single crystals into a scale-free pattern of dislocation avalanches characterized by intermittency, power-law distributions of avalanche sizes, complex space-time correlations and aftershock triggering. Here, we address the question of whether such scale-free, close-to-critical dislocation dynamics will still apply to polycrystals. We show that polycrystalline plasticity is also characterized by intermittency and dislocation avalanches. However, grain boundaries hinder the propagation of avalanches, as revealed by a finite (grain)-size effect on avalanche size distributions. We propose that the restraint of large avalanches builds up internal stresses that push temporally the dynamical system into a supercritical state, off the scale-invariant critical regime, and trigger secondary avalanches in neighbouring grains. This modifies the statistical properties of the avalanche population. The results might also bring into question the classical ways of modelling plasticity in polycrystalline materials, based on homogenization procedures.
Not file

Dates and versions

insu-00374916 , version 1 (10-04-2009)

Identifiers

Cite

Thiebaud Richeton, Jérôme Weiss, François Louchet. Breakdown of avalanche critical behaviour in polycrystalline plasticity. Nature Materials, 2005, 4, pp.465 à 469. ⟨10.1038/nmat1393⟩. ⟨insu-00374916⟩
19 View
0 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More