The simulated images from a cylindrical inclusion were compared with dislocation images. It was found that the images were very similar, and differed only with respect to the structure within the intermediate image. By adding inclusion strain fields of various magnitudes to that of the dislocation, the value at which the dislocation image became detectably different was determined. The images which were formed by this model for a decorated dislocation were compared with those that were simulated by assuming a random distribution of spherical precipitates within a cylindrical volume that surrounded the dislocation line. It was shown that the agreement of the images was very good; thus indicating that the computationally simpler cylindrical inclusion constituted a satisfactory model for a decorated dislocation. For equivalent images, the ratio of the strain parameters for the 2 models varied linearly. It was greatest for low-order reflections, and this was attributed to the differing diffracting volumes within equivalent misorientation contours for the 2 models. The separation at which 2 separate decorated dislocations could be resolved was determined as a function of precipitate size for a given precipitate density.

Simulation of Decorated Dislocation Images in X-Ray Section Topographs. A.J.Holland, B.K.Tanner: Philosophical Magazine A, 1996, 73[5], 1451-74