Avalanches in 2D Dislocation Systems: Plastic Yielding Is Not Depinning

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Journal Title
Journal ISSN
Volume Title
School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2014
Major/Subject
Mcode
Degree programme
Language
en
Pages
235501/1-5
Series
Physical Review Letters, Volume 112, Issue 23
Abstract
We study the properties of strain bursts (dislocation avalanches) occurring in two-dimensional discrete dislocation dynamics models under quasistatic stress-controlled loading. Contrary to previous suggestions, the avalanche statistics differ fundamentally from predictions obtained for the depinning of elastic manifolds in quenched random media. Instead, we find an exponent τ=1 of the power-law distribution of slip or released energy, with a cutoff that increases exponentially with the applied stress and diverges with system size at all stresses. These observations demonstrate that the avalanche dynamics of 2D dislocation systems is scale-free at every applied stress and, therefore, cannot be envisaged in terms of critical behavior associated with a depinning transition.
Description
Keywords
dislocation avalanches, quasistatic stress-controlled loading
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Citation
Ispánovity, Péter Dusán & Laurson, Lasse & Zaiser, Michael & Groma, István & Zapperi, Stefano & Alava, Mikko J. 2014. Avalanches in 2D Dislocation Systems: Plastic Yielding Is Not Depinning. Physical Review Letters. Volume 112, Issue 23. 235501/1-5. ISSN 0031-9007 (printed). DOI: 10.1103/physrevlett.112.235501.