Abstract
It is well known that the X-ray stress measurement is a unique and effective method of measuring stress, both micro and macro, in polycrystalline metals. So it is applied in wide fields of material engineering studies. There are a few problems, however, regarding the fundamentals of X-ray stress measurement. The metallic materials in practical use are polycrystalline, and in the X-ray stress measurement it is the average intraplane lattice strain, with a certain number of crystals favorably oriented with respect to the radiated characteristic X-rays, that is measured. Consequently, it is considered that the lattice strains observed by X-ray diffraction are closely related to the elastic or plastic anisotropy of the crystal grains, the direction of stress and the complex deformation mechanism.
On the effect of crystal anisotropy on the X-ray stress measurement reports of studies have so far been made by several investigators, and it is pointed out that the stress value differs in its measurement from one lattice plane to another on which the X-ray diffraction line is reflected. Though discussions on these problems have thus been made to a certain extent of X-ray measurement of the lattice strains, and of its dependence on the diffraction plane of the crystal, its details remain vague yet.
In order to solse these problems, the authors have attempted certain theoretical treatment based on six equations of generalized Hooke's law on the crystal elasticity, and compared them with experimental results of crystal plane dependence of lattice strains which was obtained from the X-ray stress measurement of low carbon steel, using (310), (211) and (220) diffraction lines. Detailed accounts of the experiments and the conclusion of this study are to be comprehensively given in the following paper.
