Discrete dislocation dynamics (DD) simulations in conjunction with stereo and in situ straining transmission electronic microscopy (TEM) were used to study dislocation motion in thin Cu foils. Stereo imaging prior to and following in situ tensile straining is utilized to describe the three-dimensional (3D) evolution of dislocation structures with incremental straining and observation by TEM. Th...

Simple shear of a constrained strip is analyzed using both discrete dislocation plasticity and strain gradient crystal plasticity theory. Both single slip and symmetric double slip are considered. The loading is such that for a local continuum description of plastic flow the deformation state is one of homogeneous shear. In the discrete dislocation formulation the dislocations are all of edge c...

A combined analytical and computational model is developed to study the mechanics of strained epitaxial island growth in typical semiconductor systems. Under certain growth conditions in systems with a film/substrate lattice mismatch, deposited material is known to aggregate into islandlike shapes with geometries having arc shaped cross-sections. A two-dimensional model assuming linear elastic ...

Transmission electron microscopy (TEM), high-resolution X-ray di!raction, and KOH etching have been used to study the dislocation structure of 4H SiC crystals grown by the physical vapor transport method. Many of the etch pits on the Si(0 0 0 1) surface form arrays extending along the S11 1 0 0T directions. Plan view conventional and high-resolution TEM show that the arrays consist of pure edge...

The core structures of screw and edge dislocations on the basal and prism planes in Mg, and the associated gamma surfaces, were studied using an ab initio method and the embedded-atom-method interatomic potentials developed by Sun et al and Liu et al. The ab initio calculations predict that the basal plane dislocations dissociate into partials split by 16.7 Å (edge) and 6.3 Å (screw), as compar...

We study consistent collections of random fragmentation trees with random integervalued edge lengths. We prove several equivalent necessary and sufficient conditions under which Geometrically distributed edge lengths can be consistently assigned to a Markov branching tree. Among these conditions is a characterization by a unique probability measure, which plays a role similar to the dislocation...

Elastic field coupling to solute concentration is known to produce dislocationdriven impurity segregation. Recent reports detailing the distribution of boron around edge dislocations in B2-ordered FeAl indicate that nonlinear coupling of species concentration and elastic strain to the chemical potential must be considered to assess the magnitude of boron segregation around edge dislocations. On...

Thin films of symmetric diblock copolymers on a flat solid surface form lamellae parallel to the substrate. The uppermost layer of the film may be incomplete and made of domains with a thickness equal to the lamellar period L. We investigate these domains both theoretically and experimentally. The domain edge is associated with a dislocation in the lamellar order which has been observed by tran...

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...