THE RELATIONSHIP BETWEEN MICROTEXTURE AND GRAIN-BOUNDARY PARAMETERS

The orientations of individuals grains in an Ni-based superalloy have been measured by a new electron back scattering technique. This microtexture analysis is applied in conjunction with a scanning electron microscope, enabling the orientations of large numbers of grains to be acquired in a short time. Also the data has been collected in a grain specific manner, so that the orientations of large grains (which are a common feature of the grain structure of this alloy) may be assessed separately to the orientations of small grains. Microtextural differences between the small- and large-grain data sets were apparent and were found to be a function of the distribution of the large grains. Furthermore, the grain texture was shown to have a significant effect on the grain misorientation texture. The proportion of boundaries very close to a coincident site lattice geometry was small, and this was interpreted in terms of the relationship between boundary solute supersaturation and boundary misfit.