| Popis: |
Semiempirical methods for extracting quantitative information from field-ion micrographs are described. The distinction between average and local magnification is quantified, and a number of new geometrical relationships are derived. New methods for indexing micrographs, for assessing image magnification and for determining tip shapes are presented. These methods improve the accuracy with which the parameters describing the angular misorientation of a grain boundary can be determined. Tip profiles reconstructed using these methods are in excellent agreement with those-derived from electron microscopy. In addition it is shown how grain boundary topography can be investigated, to an accuracy of 5–10 A, over the whole of the imaging region. |
