Dislocation-Source Shutdown and the Plastic Behavior of Single-Crystal Micropillars

Abstract

Dislocation dynamics simulations have been used to study the stress-strain response of single-crystal micropillars containing initial dislocation networks generated via a relaxation procedure intended to approximate real thermal annealing processes. We find that, when such networks are loaded, they exhibit periods of plastic deformation, caused by the operation of single junction-stabilized spiral sources, followed by intervals of purely elastic straining when the sources shut down. The results provide insight into the mechanisms responsible for the experimentally observed staircase stress-strain behavior.