EXTINCTION AND GRAIN-SIZE ANISOTROPY CORRECTION OF TEXTURE DATA OBTAINED USING NEUTRON-DIFFRACTION

The neutron diffraction method of texture determination yields informa tion concerning the orientation distribution function of the volume of crystallites. The scattered intensity depends not only on the irradia ted volume, but also on the crystallographic perfection of crystallite s and on the angular disorientation between them. Therefore, when the texture of coarse-grained materials like grain-oriented silicon steels is determined using neutron diffraction, the measurements are affecte d by errors due to the extinction phenomenon within individual grains. Additionally, the anisotropy of grain shape induces orientation varia tions of the intensity of the diffracted beam. To investigate the infl uence of extinction on texture measurements, neutron diffraction data have been collected for a composite 3% Si-Fe sample with different deg rees of lattice perfection. A correction is proposed to eliminate the effects of the orientation dependence of grain size and extinction on texture measurements.