Formation of two edge dislocations in a grain due to interface disclination dipoles

The formation of a dipole of edge dislocations inside one grain separated from the adjacent grains by two interfaces in which are lying disclination dipoles (one in each interface) has been theoretically investigated from an energy variation calculation. Critical grain sizes associated with the formation of the edge dislocation dipole have been determined as well as an activation energy. The effects of the inclination angle of the gliding plane of the dislocations and the characteristic parameters of the disclination dipoles have been finally analyzed.

Novel cloaking lamellar structures for a screw dislocation dipole, a circular Eshelby inclusion and a concentrated couple

Using conformal mapping techniques, we design novel lamellar structures which cloak the influence of any one of a screw dislocation dipole, a circular Eshelby inclusion or a concentrated couple. The lamellar structure is composed of two half-planes bonded through a middle coating with a variable thickness within which is located either the dislocation dipole, the circular Eshelby inclusion or the concentrated couple. The Eshelby inclusion undergoes either uniform anti-plane eigenstrains or uniform in-plane volumetric eigenstrains. As a result, the influence of any one of the dislocation dipole, the circular Eshelby inclusion or the concentrated couple is cloaked in that their presence will not disturb the prescribed uniform stress fields in both surrounding half-planes.