(a) Enlarged area around the two fibers indicated by red arrows in Fig. 3(j). (b) Area at the edge of the specimen, just above `#' in Fig. 3(i). In (a)–(b), the horizontal field is 100 voxels. White represents high and black low attenuation, and a small number (<5 vol.%) of high-attenuation impurity particles are scattered throughout. (c) Profiles through the center of the fibers shown in (a) for the 220 Al and 11.0, 10.1 and 10.2 SiC reconstructions.