Textures in Non-Metallic Materials

Abstract

The texture of a polycrystalline material is defined by the orientation distribution function (ODF) of its crystallites. Besides this, the misorientation distribution MODF of neighbouring crystals may be important. Although this applies equally to all crystalline materials, texture studies have extensively been done in metals and not so much in ceramics and polymers. This is partly due to experimental difficulties of texture measurement in these materials which have only recently been overcome. Besides this, two deviating definitions of the term ”texture” are being used. These are the ”shape texture” in ceramics and the ”chain texture” in polymers.Textures in ceramics were studied quantitatively mainly in hard magnetic materials. They are, however, also most important in HT_c-superconductors, in ferroelectrics, in transformation toughened ceramics, in ceramic surface layers, copperbonded Al₂O₃ substrates and probably in many others. Textures in the crystalline part of polymers have been studied quantitatively using ODF-methods. ”Momenta” of the orientation distribution function of the crystalline as well as the non-crystalline part can, however, be obtained more easily by physical methods. This is sufficient if the correlation between preferred orientation and anisotropic properties is considered. Texture formation by deformation is, however, related to the complete orientation distribution function.