Large twist-angle grain boundaries in layered structures are often described by Scherk's first surface whereas small twist-angle grain boundaries are usually described in terms of an array of screw dislocations. We show that there is no essential distinction between these two descriptions and that, in particular, their comparative energetics depends crucially on the core structure of their scre...

Previous density functional theory (DFT) studies of the 1/3 h1 210i screw dislocation in titanium have shown metastable core structures depending on the initial position of the dislocation line. We investigate this problem by modeling a screw dislocation with two initial positions using both DFT and a modified embedded atom (MEAM) potential for Ti with flexible boundary conditions. Both DFT and...

Using QM-Sutton-Chen many-body potential, we have studied the 1⁄2a<110> screw dislocation in nickel (Ni) via Molecular Dynamics (MD) simulations. We have studied core energy and structure using a quadrupolar dislocation system with 3-D periodic boundary conditions. The relaxed structures show dissociation into two partials on {111} planes. The equilibrium separation distance between the two par...

Plasticity in body-centred cubic (BCC) metals at low temperatures is atypical, marked in particular by an anisotropic elastic limit in clear violation of the famous Schmid law applicable to most other metals. This effect is known to originate from the behaviour of the screw dislocations; however, the underlying physics has so far remained insufficiently understood to predict plastic anisotropy ...

The study of dislocations interacting with interfaces is of great interest to understand the strengthening and hardening mechanisms in materials. Most of the existing results in this field dealt with perfect interfaces where the displacements are continuous across interfaces. In reality, however, due to damage of interfaces or other reasons, the displacements across interfaces could have a jump...

abstract traumatic hip dislocations are common in high-energy motor vehicle accidents. we present a case of a 43-year old man who sustained posterior hip dislocation with posterior wall acetabular fracture and ipsilateral intertrochantric fracture following a motorcycle accident. urgent open reduction and internal fixation of the hip fracture-dislocation and fixation of intertrochantric fractur...

A method for calculating the anisotropic elastic energy of a dislocation dipole in a periodic cell is derived in which the infinite image summation is absolutely convergent. The core energy of a screw dislocation in Si, extracted from atomistic simulation, is shown to be manifestly system size invariant. Existence of special cell geometry where complete cancellation of elastic interactions occu...

A (microscopic) static elastoplastic field theory of dislocations with moment stress is considered. The relationship between the moment stress and the Nye tensor is discussed and used for the dislocation Lagrangian. We discuss the stress field of a screw dislocation which is modified in the core region due to the appearance of moment stress.

For treatment of acute acromioclavicular dislocation we chose operative treatment in which we fixed clavicule to coracoid with a screw. With regard to the clinical results, out of 6 patients who had gone under operation, only one had calcification at coracoclavicular ligament without limitation of motion. There were no serious postoperative complication. 

This letter is concerned with an interfacial edge crack in a piezoelectric bimaterial wedge interacting with a screw dislocation under antiplane mechanical and in-plane electric loading. In addition to a discontinuous electric potential across the slip plane, the dislocation is subjected to a line-force and a line-charge at the tip. The out-of-plane displacement and electric potentials are obta...