Strain gradient influence on dislocation dynamics

Dislocations are topological defects known to be crucial in the onset of plasticity and in many properties of crystals. Classical Elasticity still fails to fully explain their dynamics under extreme conditions of high strain gradients and small scales, which can nowadays be scrutinized. Recently [1], by separating conformal and shape deformations, we constructed a new formalism for two-dimensional (2D) Elasticity and described edge dislocations as finite disclination dipoles. This led us to heuristically obtain that dislocations can be driven by a force that is induced by background density (or hydrostatic strain) gradients. The existence of such mechanism is confirmed through atomistic simulations [1], where we can move and trap individual dislocations using such configurational force. This talk presents an insight about the physical mechanism responsible for this driving force. It also shows how to design atomistic simulations that can quantitatively measure the effects of strain gradients on dislocations.

[1] Pereira, P. C. N. and Apolinario, S. W. S. arXiv:1807.04321 (2018).

The authors acknowledge the support of the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).