Reproducible Textures

Abstract

The orientation distribution function of a textured polycrystalline material may be split into an even and odd part; the latter is not reproducible from pole figure measurements as has been recently shown. The class of textures containing only a reproducible part is considered. In the case of axially symmetric textures (fibre textures), these take on a very simple form. They are, however, not the only type of reproducible textures as has been assumed. A sample having a reproducible texture is centrosymmetric, even in the most general case of non-centrosymmetric, enantiomorphic crystals of one crystal form only. Symmetry elements of this kind have been called non-conventional ones. They may be described by black-and-white or Shubnikov groups. Reproducible textures correspond to a non-conventional centre of inversion as an element of sample symmetry and vice versa.