Dislocation jamming and Andrade creep

TL;DR

This paper uses simulations to demonstrate that dislocation interactions under shear stress exhibit Andrade creep, driven by correlated dislocation motion near a dynamic transition between flowing and jammed states.

Contribution

It reveals that Andrade creep arises from correlated dislocation dynamics near a critical transition, incorporating effects of multiplication and noise for robustness.

Findings

Andrade creep follows from dislocation interactions.

Dislocation structures undergo a dynamic transition.

Metastable structures influence relaxation behavior.

Abstract

We simulate the glide motion of an assembly of interacting dislocations under the action of an external shear stress and show that the associated plastic creep relaxation follows Andrade's law. Our results indicate that Andrade creep in plastically deforming crystals involves the correlated motion of dislocation structures near a dynamic transition separating a flowing from a jammed phase. Simulations in presence of dislocation multiplication and noise confirm the robustness of this finding and highlight the importance of metastable structure formation for the relaxation process.