Method of Evaluating Geometrical‐Statistical Parameters of the Interaction between Dislocations and Point Obstacles from Electron Micrographs

Abstract

Abstract Electron micrographs of MgO crystals deformed in the HVEM show screw dislocations of curly shape. The dislocations are pinned at localized obstacles and bow out between them. The paper describes a measuring procedure for the geometrical interaction parameters between the dislocations and the obstacles. Such are the effective stress, the obstacle distance and the force acting on the obstacles. The procedure consists in a graphical fit of loops calculated by the DE WITT‐KOEHLER line tension model to the observed dislocation segments.