THE ENERGY OF CONSTRICTIONS IN EXTENDED DISLOCATIONS

The shape and energy of screw dislocation constrictions is calculated numerically according to the principles of linear, anisotropic elasticity theory, in contrast to previous treatments which did not correctly take into account all interaction energies. The energy of the whole constriction configuration can be conveniently written as the energy of two isolated half-constrictions plus the energy of the completely compressed straight piece between them. Suitably normalized, the half-constriction energy does not depend very strongly on specific material properties. In first approximation, it can be calculated by a simple rule, provided extension width or stacking fault energy are known.