A (microscopic) static elastoplastic field theory of dislocations with moment and force stresses is considered. The relationship between the moment stress and the Nye tensor is used for the dislocation Lagrangian. We discuss the stress field of an infinitely long screw dislocation in a cylinder, a dipole of screw dislocations and a coaxial screw dislocation in a finite cylinder. The stress fiel...

We study the excitation of harmonic waves in thin elastic samples by a single dislocation in arbitrary motion. We consider both screw and edge dislocations that move perpendicularly to the surfaces of the layer. In Fourier space the displacement velocity and dynamic stress fields generated by the motion of the dislocations are factored as the product of two terms: one depends on the motion of t...

Dislocation mobility is a fundamental material property that controls strength and ductility of crystals. An important measure of dislocation mobility is its Peierls stress, i.e., the minimal stress required to move a dislocation at zero temperature. Here we report that, in the body-centered cubic metal tantalum, the Peierls stress as a function of dislocation orientation exhibits fine structur...

Employing the empirical embedded-atom method potentials, the evolution of edge and screw dislocation core structure is calculated at different hydrogen concentrations. With hydrogen, the core energy and Peierls potential are reduced for all dislocations. A broaden-core and a quasi-split core structure are observed for edge and screw dislocation respectively. The screw dislocation and hydrogen i...

Screw dislocations play an important role in materials' mechanical, electrical and optical properties. However, imaging the atomic displacements in screw dislocations remains challenging. Although advanced electron microscopy techniques have allowed atomic-scale characterization of edge dislocations from the conventional end-on view, for screw dislocations, the atoms are predominantly displaced...

Dislocation slip is investigated in a metastable  titanium alloy with the Ti-23Nb-0.7Ta-2Zr0.4Si composition (at. %) by in situ straining experiments in a transmission electron microscope (TEM). Moving dislocations have a/2<111> Burgers vectors and glide in {110}, {112} or {123} planes. The mobility of screw dislocations is lowered by punctual defects and the existence of a stable and sessile ...

Dislocation bias factors in bcc Fe have been calculated based on atomistic interaction energy maps on three kinds of dislocations, namely the a0/2〈111〉{110} screw, a0/2〈111〉{110} and a0〈100〉{001} edge dislocations. The results show that the dislocation bias is higher for the a0/2〈111〉 edge dislocation than for the a0〈100〉 edge dislocation, even though the latter possesses a larger Burgers vecto...

Self-diffusion along screw and edge dislocations in Al is studied by molecular dynamics simulations. Three types of simulations are performed: with pre-existing vacancies in the dislocation core, with pre-existing interstitials, and without any pre-existing defects (intrinsic diffusion). We find that diffusion along the screw dislocation is dominated by the intrinsic mechanism, whereas diffusio...