Dislocation কী?

A dislocation is a line defect in a crystal: the boundary, inside the crystal, between a part of a lattice plane that has slipped and a part that has not. Its Burgers vector $\mathbf b$ is the slip that it carries, one lattice spacing in a lattice direction. In an edge dislocation $\mathbf b$ is perpendicular to the line, which is the edge of an extra half-plane of atoms; in a screw dislocation it is parallel to the line. A dislocation moves by glide on its slip plane, and an edge dislocation leaves that plane by climb, as atoms or vacancies diffuse to or from the edge of its half-plane.