Elastic properties of polycrystals - influence of texture and stereology

The macroscopic elastic properties of polycrystalline materials depend on t he elastic properties of the crystallites and the way how these are 'arrang ed' in the polycrystalline aggregate. This comprises the volume fraction of crystal orientations (texture) as well as their arrangement in space (ster eology). It is estimated that the stereological aggregate parameters may co ntribute up to 25% of the maximum texture influence. Model calculations of the effective macroscopic elastic properties were carried out using a grain cluster model which is a finite discretization of the aggregate function g (x) describing the complete 'orientation-stereology' of the polycrystalline material. The most important stereological parameters influencing the effe ctive elastic constants are grain shape expressed by two axis ratios, grain packing expressed by the space filling factor of the lattice of grain cent res and orientation pair correlation of neighbouring grains expressed by th e misorientation distribution function. By rotating the orientation of only one grain it can be shown that grain interaction strains decrease rapidly and may be neglected beyond the second order neighbours. (C) 1999 Elsevier Science Ltd. All rights reserved.