Inertial Oscillations of Pinned Dislocations

TL;DR

This paper reports the first observation of inertial, damped oscillations of pinned dislocations in crystals, revealing insights into dislocation dynamics and potential links to electromagnetic emissions during deformation.

Contribution

It presents the first experimental observation of inertial dislocation oscillations and analyzes their damping, mass, and frequency relations, challenging existing theoretical models.

Findings

Dislocations exhibit inertial damped oscillations after pinning.

Damping rate allows estimation of dislocation effective mass.

Anomalous relation between oscillation frequency and link length was observed.

Abstract

Dislocation pinning plays a vital role in the plastic behaviour of a crystalline solid. Here we report the first observation of the damped oscillations of a mobile dislocation after it gets pinned at an obstacle in the presence of a constant static shear load. These oscillations are found to be inertial, instead of forced as obtained in the studies of internal friction of solid. The rate of damping enables us to determine the effective mass of the dislocation. Nevertheless, the observed relation between the oscillation frequency and the link length is found to be anomalous, when compared with the theoretical results in the framework of Koehler's vibrating string model. We assign this anomaly to the improper boundary conditions employed in the treatment. Finally, we propose that the inertial oscillations may offer a plausible explanation of the electromagnetic emissions during material deformation and seismic activities.