MEASUREMENT AND REPRESENTATION OF GRAIN-BOUNDARY TEXTURE

The measurement and representation of grain-boundary texture in single-phase polycrystals are examined in this article. Grain-boundary texture is assumed to be fully defined by the lattice orientation of two grains which come together to form the boundary and by the orientation of the boundary relative to the two lattices. Representations which incorporate more limited definitions of local grain-boundary structure are easily considered in natural subspaces of the more complete representation. The two major stereologies which have been developed for measuring grain-boundary texture from random sectioning are compared in detail. It is demonstrated that the stereological method of Hilliard,[3] which obtains the distribution of boundary normals from intersections of the boundaries with random test lines placed on random sections, cannot distinguish sided" grain-boundary textures. The stereological method of Adams,[4] which obtains the boundary normal distribution from the angular distribution of boundary intersections in random sections, is shown to be more general, since it is not limited to "nonsided" grain-boundary textures. It is also shown that the latter stereology obtains a more accurate representation of the boundary-normal distribution, as compared with the former, for an equivalent number of section planes.