Electron Microscopic Images of Single and Intersecting Stacking Faults in Thick Foils II. Intersecting Faults

The dynamic theory of electron transmission microscopic images of intersecting stacking faults is developed and discussed. Intersecting faults of the same type in f.c.c. alloys are considered, the fault planes having opposite tilt. The expected images are compared with observations on thick Cu‐15% Ga foils. The aspects of the bright‐field images are different under different diffraction conditions: (i) “streaked” fringes parallel to the projection of the intersection line for large values of the excitation error s; (ii) for small values of s the images consist of two distinct parts: the central one and the outer one. The central part consists of a few nearly unmodulated straight fringes parallel to the intersection. The outer part is a more or less deformed superposition of two fringe patterns. A pure superposition of the fringe patterns due to each fault separately is found for a particular value of s and for the outer part of the image. The qualitative features of the image for small s in thick foils are due to anomalous absorption effects.