The influence of some geometrical and physical factors on the diffraction patterns of polycrystals

Abstract

A method of grain size determination in polycrystals from the number of spots on Debye-Scherrer rings serves here as experimental basis for the study of the influence of a) parameters of the experimental arrangement (e.g., divergence of primary beam, choice of the standard blackening and ratio of exposures), and b) properties of the specimen (e.g., preferred orientation of grains and their local distribution of sizes), on the results of measurement. Sufficiently numerous statistical sets of experimental data show that the counting of spots may be quite exact, but the usually applied relation between the number of spots and grain size is likely appreciably oversimplified. As the assumptions, from which the mentioned relation was deduced, are closely connected with problems of X-ray diffraction, the results presented in this paper may be interesting from a more general point of view. The X-ray results are also compared to the metallographic ones.