ABSTRACT
Representation of grain and phase boundaries in terms of misorientation alone is achieved via the usual orientation parameters. namely the Euler angles, anglelaxis pair or Rodrigues vector (Chapter 2). The most popular extension categorisation of misorientation for grain boundaries is the coincidence site lattice model which is explained in Section 1 1.2.1. However, ,five independent variables are required to specify the crystallographic orientation of a surface (Section 11.2.2), and the misorientation only supplies three. A full analysis of a planar surface requires spatial information, additional to the grain orientation. in order to calculate the crystallographic indices. In this Chapter the methodologies of such investigations: and some applications, are described (Section 11.3). Although grainiphase boundaries and slip traces can be analysed in the TEM, there are considerable disadvantages, mainly in terms of statistical reliability. Furthermore, analysis of cracks or external specimen surfaces is not possible in the TEM because of specimen preparation restrictions. On the other hand SEM is ideal for studying the morphology of surfaces and so it is mainly EBSD that has been adapted to crystallographic studies of surfaces. Such applications of EBSD tend to be customised (e.g. Case Study No. 4) and are not yet mainstream as for studies involving only orientations and misorientations.
