ABSTRACT
A microtexture is, essentially, a population of individual orientations which can be linked to their location in a specimen and are obtained usually by an electron diffraction technique as described in Chapters 7 and 8. These two factors - the discrete nature of the orientation data and their direct link to the microstructure - introduce a much broader and more complex scenario for data evaluation and representation than that for macrotextures, since in the latter case the orientation data evaluation usually involves only direct representation in the form of pole figures and subsequently calculation of an ODF (Chapter 5) . The large variety of situations which can be addressed by means of single grain orientation measurements requires many more formats for the representation and interpretation of the measurements. The nature of microtexture gives rise to two fundamental lines of inquiry:
Statistical distribution of orientation and misorientation data
Orientation and inisorientation data related to the microstructure
For most investigations both of these analysis steps will be required, and the data will be selected from relatively small regions of interest. There are two ways in which orientation and misorientation microtexture data can be displayed in a space: as discrete data points or as a continuous density distribution. For simplicity in the case of the latter we will use the terminology ‘orientation (or misorientation) distribution ,fiiizctiorz’ for a11 continuous distributions, without distinguishing if the function applied involves the series expansion method (as for macrotexture data) or the more simple case of a direct contouring function. This has the advantage of allowing generic terminology to be used for both macrotexture and all continuous microtexture data. Some texts, however, reserve use of the term ‘(mis)orientation distribution function, (M)ODF, in microtexture for series expansion methods only, and refer to direct contouring as a ‘(1nis)orientation distribution’.
