Intermittent microplasticity in the presence of a complex microstructure

We demonstrate the gradual shift from scale-free intermittent microplasticity to a scale-dependent behavior via the introduction of a variety of microstructural features within the Al-Cu binary alloy system. As long as the obstacles to dislocation motion remain shearable, the statistics of intermittent microplasticity has fat-tailed contributions. The introduction of incoherent precipitates leads to a complete transition from scale-free powerlaw scaling to an exponential and scale-dependent distribution. These results demonstrate how non-Gaussian interactions survive across different microstructures and further suggest that characteristic microstructural length scales and obstacle pinning-strengths are of secondary importance for the intermittency statistics, as long as dislocations can shear their local environment.

Automated summary

In this study, we demonstrate the gradual transition from scale-free powerlaw scaling to exponential and scale-dependent distribution by introducing various microstructural features in an Al-Cu binary alloy system. The statistics of intermittent microplasticity exhibit fat-tailed contributions as long as the obstacles to dislocation motion can be sheared. The introduction of incoherent precipitates leads to a complete transition in the statistical behavior, suggesting that microstructural length scales and obstacle pinning-strengths are of secondary importance.