A series of the Al-Pd-Mn icosahedral crystals grown by the Czochralski tech
nique was examined by X-ray topography in order to determine their mosaic s
tructure. The Auleytner method with the point X-ray source was applied. It
was found that there are three characteristic types of block structure with
different degrees of mosaicity from 5' to 2 degrees. All blocks have sharp
images on the X-ray topographs. In several cases, we have observed diffuse
d images of the low-angle boundaries as well as diffused contours of the X-
ray topography images. (C) 2000 Elsevier Science B.V. All rights reserved.