Plastic deformation in crystalline materials consists of an ensemble of collective dislocation glide processes, which lead to strain burst emissions in micro-scale samples. To unravel the combined role of crystalline structure, sample size and temperature on these processes, we performed a comprehensive set of strict displacement-controlled micropillar compression experiments in conjunction with large-scale molecular dynamics and physics-based discrete dislocation dynamics simulations. The results indicate that plastic strain bursts consist of numerous individual dislocation glide events, which span over minuscule time intervals. The size distributions of these events exhibit a gradual transition from an incipient power-law slip regime (spanning [Formula: see text] 2.5 decades of slip sizes) to a large avalanche domain (spanning [Formula: see text] 4 decades of emission probability) at a cut-off slip magnitude [Formula: see text]. This cut-off slip provides a statistical measure to the characteristic mean dislocation swept distance, which allows for the scaling of the avalanche distributions vis-à-vis the archetypal dislocation mechanisms in face-centered cubic (FCC) and body-centered cubic (BCC) metals. Our statistical findings provide a new pathway to characterizing metal plasticity and towards comprehension of the sample size effects that limit the mechanical reliability in small-scale structures.

Department of Materials Science and Metallurgical Engineering InSup ETSEIB Universitat Politècnica de Catalunya 08028 Barcelona Spain

Department of Mechanical Engineering Whiting School of Engineering The Johns Hopkins University Baltimore MD 21218 USA

Institute of Thermomechanics Czech Academy of Sciences 182 00 Prague 8 Czech Republic

Laboratory for Mechanics of Materials and Nanostructures Empa Swiss Federal Laboratories for Materials Science and Technology 3602 Thun Switzerland

Laboratory for Nanometallurgy Department of Materials Swiss Federal Institute of Technology in Zürich Vladimir Prelog Weg 5 CH 8093 Zürich Switzerland

New Technologies Research Centre University of West Bohemia in Pilsen 30614 Plzeň Czech Republic

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Dislocation avalanches are like earthquakes on the micron scale