Computed Electron Micrographs for Tilted Foils Containing Dislocations and Stacking Faults

Abstract

The method of computation of electron microscope images developed by Head (1967) produces micrographs of single dislocations in about 1 min of numerical integration. In Head's original programme, the electron beam direction and the normal to the foil surface are coincident. Since this condition is not often realized in practical electron microscopy, the programme has been extended to compute the images of dislocations in tilted foils. It has been further modified to compute he images from a configuration 'containing up to two dislocations and up to three stacking faults. These programmes are thus applica.ble to a wide range of defect con· figurations in tilted thin foils. The derivation of these programmes is described and several examples of their- use in experimental situations are given. These include the "skewing" of dislocation images due to the noncoincidence of the beam direction and the foil normal, and images due to interactions between dislocations and stacking faults.