Papers by Keyword: Crystallite Group Method

Abstract: X-ray diffraction stress analysis by crystallite group method (CGM) has been employed in case of simultaneously strong and sharp fiber textured Ti thin films. These Ti films exhibit thickness dependent hcp-fcc phase transformation [Ref. 1]. Diffraction stress analysis has also been attempted by d-sin2 method for strongly textured face centered cubic (fcc) and hexagonal close packed (hcp) Ti phases. For hcp Ti phase, the results of stress analysis by CGM are compared with those obtained from d-sin2 method. It is found that the stress values in hcp Ti phases obtained from CGM considerably differ from the stresses obtained from d-sin2 method in some of the Ti films. Observed differences have been explained and possible sources of errors in d-sin2 method and CGM stress analysis have been discussed.

Abstract: The so-called crystallite group (CGM) method, employed for diffraction stress analysis, involves that a possibly complex texture is approximated by a set of one or a few so-called ideal orientations. It has been shown that this approximation can lead to pronounced errors in the determined stress values. The range of applicability of the CGM has been investigated from a theoretical point of view. Numerical simulations of diffraction strain measurements have been performed using orientation distribution functions representing textures of different strength and sharpness. Special emphasis has been put on the fibre-textured case.