ABSTRACT

There is a basic divide between macrotexture techniques (based on x-ray or neutron diffraction; Chapters 4 and 5) and microtexture techniques (based usually on electron diffraction; Chapters 7 through 11), which relates to the scale of the inquiry and hence affects the nature of the primary output data. For macrotexture techniques, the primary output is a pro le of diffracted intensities, which is characteristic of a large contiguous sample volume, whereas for microtexture-individual grain-techniques, the primary output is a diffraction pattern from each sampled volume. Such a pattern embodies the complete crystallographic information inclusive of the orientation of the respective sampled volume, which usually is an individual crystallite wherein the orientation can be taken to be uniform. For a vast majority of microtexture works in both TEM and SEM, this type of pattern is a Kikuchi diffraction pattern. Other techniques occasionally used are SAD, which still has applications in TEM (Section 8.3), and the micro-Kossel technique, which has applications in SEM (Section 7.2).