Determination of the Burgers vector of an isolated boundary dislocation by weak-beam high-voltage electron microscopy

Abstract

The Burgers vector of an isolated boundary dislocation can be determined rigorously from three sets of weak-beam micrographs with diffracting vectors common to the adjoining crystals by equating the three aquations; θ₁(x, y, z) b(x, y, z) = n₁ (i = 1,2,3) where n is the number of extinction contours which appear to be terminated at the exit of the dislocation at either surface of the thin foil specimen The common diffraction condition OCCUK for each coincidence site lattice orientation relationship between the neighbouring crystals. A sufficient number of extinction contours were obtained with relatively high order diffractions in a smoothly polished thin foil specimen by the use of a high-voltage electron microscope. It will be shown that boundary dislocations in major coincidence boundaries can be determined by the present method.