The Peach–Koehler expressions for the glide and climb components of the force exerted on a straight dislocation in an infinite isotropic medium by another straight dislocation are derived by evaluating the plane and antiplane strain versions of J integrals around the center of the dislocation. After expressing the elastic fields as the sums of elastic fields of each dislocation, the energy mome...

Using a new, first principles based, embedded-atom-method (EAM) potential for tantalum (Ta), we have carried out molecular dynamics (MD) simulations to investigate the core structure, core energy and Peierls energy barrier and stress for the 1/2 a〈1 1 1〉 screw dislocation. Equilibrated core structures were obtained by relaxation of dislocation quadrupoles with periodic boundary conditions. We f...

Hydride vapour phase epitaxy grown allepitaxial p-i-n structures were studied by synchrotron X-ray topography. Three types of process induced dislocations were found: short threading dislocations, long straight interfacial dislocations and circular arc dislocations. The majority of the dislocations observed are short straight threading dislocations, the density of which is typically about 5000 ...

In this manuscript, we extend on our prior work to show that under certain conditions cross-slip nucleation is athermal and spontaneous with zero activation energy in FCC elemental metals such as Ni and Cu, and L12 intermetallic compounds such as Ni3Al. Using atomistic simulations (molecular statics), we show that spontaneous cross-slip occurs at mildly repulsive intersections. Further, the loc...

Simultaneous middle third clavicle fracture and acromioclavicular joint dislocation is a rare combination injury, as a result of high-energy trauma. We report a patient with a middle third clavicle fracture and ipsilateral grade three-acromioclavicular joint dislocation, which is a rare combination. The patient wanted to get back to work as soon as possible, so the fracture was fixed with recon...

The density and the character of dislocations and the size-distribution of grains or subgrains were determined by a new procedure of X-ray diffraction (XRD) profile analysis in copper specimens deformed by equal channel angular pressing (ECA) or cold rolling. The anisotropic strain broadening of diffraction profiles was accounted for by dislocation contrast factors. The screw or edge character ...

A framework for investigating plasticity phenomena and their dependence on the underlying physical and size-dependent mechanisms is developed. The framework is based on crystal plasticity and three-dimensional discrete dislocation dynamics analyses. Particularly, the mesoscale model couples continuum crystal plasticity framework with a set of spatio-temporal evolution equations for dislocation ...

Micromechanic theory of fatigue crack initiation by Lin and his associates is reviewed. Intrusions and extrusions have been observed in fatigue specimens. An initial stress field favorable for the growth of extrusion or intrusion can be produced by arrays of dislocation dipoles as shown by Lin (1969). These dipoles cause an initial tensile strain giving an elongation which is called the static ...