Abstract
X-ray diffraction patterns of polycrystal specimens are generally spotted. When we are to determine the residual stress of such specimens by X-rays, the specimens must be moved to produce a continuous series of diffraction rings. Using annealed low carbon steel plates, we experimentally investigated how their diffraction rings appeared under horizontal and rotative movements.
For the experiment we have used Cr Kα line of parallel beam X-rays and divergence X-rays. The X-ray diffraction patterns obtained from this experiment were invariably spotted ones extended in a specific direction which depends on the manner of the movement of the specimen. This direction agreed with the specimen movement in the case of horizontal movement, and with the direction normal to the rotative axis in the case of rotative movement.
According to the observation, the mechanism of variation in the spotted pattern differ from case to case.
Though the geometric diffractive conditions of the X-rays and specimens are the same, it has been revealed that the difference in mechanism due to the state of crystal cohesion and that due to the solar slit scattering of parallel beam X-rays are superposed upon each other.
Moreover, assuming that the X-ray diffraction pattern is caused by the Bragg reflection, we have theoretically established the conditions for diffraction ring to separate itself into Kα1 line and Kα2 line, with respect to the parallel beam X-rays and the divergence X-rays. The condition thus obtained agreed well with the experimental results.
In the X-ray diffraction patterns obtained from the experiment, a diffraction pattern for the satellite line of Kα line could be recognized.
