X線的弾性定数の回折面依存性について

抄録

In making X-ray measurements of materials under known uniaxial elastic stress, we can determine the X-ray elastic constants S₁ and S₂/2 experimentally. Of the same material, however, the measured values of the X-ray elastic constants usually vary with the wavelength of the radiation used, or the Miller indices of the measured lattice planes. Here, we call this the diffraction plane dependency of X-ray elastic constants.
The diffraction plane dependency of X-ray elastic constants has hitherto been discussed by many investigators analytically and experimentally. Many of them have used the different characteristic radiation in order to catch the diffraction line on the different lattice plane. But it is more reasonable to use the same characteristic radiation in the study of the diffraction plane dependency.
In this paper, the strain determination of different lattice planes was made by means of specially constructed devise attached to the X-ray diffractometer which made it possible to use the sin²ψ method not only at a high diffraction angle, but also at a very low diffraction angle, and so made it possible to use the same characteristic radiation for the study of the diffraction plane dependency of X-ray elastic constants.
In these experiments, which were carried out under uniaxial tension at various elastic stress levels, the 0.2% low-carbon steel specimens were used. The mechanism of the stress measurements is indicated in Fig. 2. The characteristic radiations and diffraction planes used are as follows; Cr Kα radiation-(110) (200) (211), FeKα radiation-(110) (200) (211) (220), CoKα radiation-(200) (211) (220) (310).
The experiments show that the measured X-ray elastic constants S₁ and S₂/2 have no relation to the wavelength of the radiation used, but depend upon the measured (hkl) lattice plane notably; that is, the absolute values of S₁ and S₂/2 on (110) and (211) lattice planes are the same and are lower than that on a (310) lattice plane. The absolute value of S₁ and S₂/2 on a (200) lattice plane is the largest, and the X-ray elastic constants have linear relation to the orientation function.