Influence of loading control on strain bursts and dislocation avalanches at the nanometer and micrometer scale

Yinan Cui, Giacomo Po, Nasr Ghoniem

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Through three-dimensional discrete dislocation dynamics simulations, we show that by tuning the mode of external loading, the collective dynamics of dislocations undergo a transition from driven avalanches under stress control to quasiperiodic oscillations under strain control. We directly correlate measured intermittent plastic events with internal dislocation activities and collective dynamics. Under different loading modes, the roles of the weakest dislocation source and the defect population trend are significantly different. This finding raises new possibilities of controlling correlated dislocation activities and obtaining a low defect density in nanostructured devices by tuning external constraints. In addition, the effect of machine stiffness comes to light. The statistical analysis of the burst magnitude is revisited and carefully discussed. Self-organized criticality and scale-free statistics of strain bursts are obeyed under stress control. However, this behavior is shown to break down under strain control. Rapid stress drops under pure strain control force truncation of dislocation avalanches, leading to a dynamical transition to quasiperiodic oscillations.

Original languageEnglish (US)
Article number064103
JournalPhysical Review B
Volume95
Issue number6
DOIs
StatePublished - Feb 8 2017
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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