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Statistics of Dislocation Slip Avalanches in Nanosized Single Crystals Show Tuned Critical Behavior Predicted by a Simple Mean Field Model

Nir Friedman (), Andrew Jennings (), Georgios Tsekenis (), Ju-Young Kim (), Molei Tao (), Jonathan Uhl (), Julia Greer (Caltech), Karin Dahmen (University of Illinois)

Discrete Dislocation Plasticity

Mon 4:20 - 5:40

Barus-Holley 157

We show that slowly sheared metallic nanocrystals deform via discrete strain bursts (slips), whose size distributions follow power laws with stress-dependent cutoffs. We show for the first time that plasticity reflects tuned criticality, by collapsing the stress-dependent slip-size distributions onto a predicted scaling function. Both power-law exponents and scaling function agree with mean-field theory predictions. Our study of 7 materials and 2 crystal structures, at various deformation rates, stresses, and crystal sizes down to 75 nm, attests to the universal characteristics of plasticity. The authors gratefully acknowlegde funding from National Science Foundation Grant DMR 100520 (KD) and CAREER Grant DMR-0748267 (JRG), and ONR Grant No. N00014-09-1-0883 (JRG). Reference: Physical Review Letters 109, 095507 (2012).