Abstract: The theoretical calculation of dislocation density in different regions of a deformed workpiece of 99.99% pure copper has been carried out using different procedures consisting of Finite Element Method (FEM) and hardness measurement. To assess the validity of the results pertaining to these procedures, the dislocation density is experimentally measured utilizing the Differential...

Equal channel angular rolling (ECAR) is a severe  plastic deformation (SPD) technique which has been used to produce metal sheets with ultra-fine grain structure. In the present work, the relationships between the mechanical properties and microstructure of samples during the ECAR process have been investigated. The Rietveld method was applied to analyze the X-ray diffraction pattern and to det...

zno thin films were deposited on si(400) substrates by e-beam evaporation technique, and then post-annealed at different annealing temperatures (200-800°c). dependence of the crystallographic structure, nano-strain, chemical composition and surface physical morphology of these layers on annealing temperature were studied. the crystallographic structure of films was studied using x-ray diffracti...

the problem of several finite moving cracks in a functionally graded material is solved by dislocation technique under the condition of anti-plane deformation. by using the fourier transform the stress fields are obtained for a functionallygraded strip containing a screw dislocation. the stress components reveal the familiar cauchy singularity at thelocation of dislocation. the solution is empl...

In this paper, the solution of a moving Volterra-type screw dislocation in an orthotropic layer, bonded between two piezoelectric layers is obtained using complex Fourier transform. The dislocation solution is then employed as strain nuclei to derive singular integral equations for a medium weakened by multiple moving cracks. These equations, which are classified as, Cauchy singular equations, ...

in this paper, the solution of a moving volterra-type screw dislocation in an orthotropic layer, bonded between two piezoelectric layers is obtained using complex fourier transform. the dislocation solution is then employed as strain nuclei to derive singular integral equations for a medium weakened by multiple moving cracks. these equations, which are classified as, cauchy singular equations, ...

Fermi-level pinning by misfit dislocations at GaAs interfaces has been investigated. n -GaInAs was used to control the misfit dislocation density by varying of composition and epilayer thickness. interfaces with zero or low dislocation densities are Ohmic to current flow, and become rectifying with increasing dislocation density. The "Schottky barrier height" increases with dislocation density ...

This paper contains a theoretical formulation of multiple interface cracks in two bonded dissimilar half planes subjected to in-plane traction. The distributed dislocation technique is used to construct integral equations for a dissimilar mediums weakened by several interface cracks. These equations are of Cauchy singular type at the location of dislocation, which are solved numerically to obta...

To investigate the effect of growth area on interface dislocation density in strained-layer epitaxy, we have fabricated 2-.um-high mesas of varying lateral dimensions and geometry in (001) GaAs substrates with dislocation densities of 1.5 X 10\ 10, and 10 cm-2 • 3500-, 7000-, and 8250-A-thick Ino (J5 Gao 95 As layers, corresponding to 5, to, and 11 times the experimental critical layer thicknes...

Size-affected dislocation-mediated plasticity is important in a wide range of materials and technologies. Here we develop a generalized size-dependent dislocation-based model that predicts strength as a function of crystal/grain size and the dislocation density. Three-dimensional (3D) discrete dislocation dynamics (DDD) simulations reveal the existence of a well-defined relationship between str...