In Situ Stress Analysis under Dynamic State by Using X-ray Diffraction

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The X-ray stress analysis is the method calculates the stress from strain of interplanner spacing, and the value is the actual stress. However, recently most of the X-ray stress analysis apply sin^2psi method which requires plural incident angles to get diffraction angle in each measurement. Therefore it is the real situation that the measurement under dynamic stress circumstances has not been carried out yet. This research is purposed on the realization of the actual stress observation under dynamic condition, it is planned to dissolve the problems by using the combination of "Single Exposure Technique", the one of the method for X-ray stress analysis, and "Position Sensitive Proportional Counter". SET is the method to measure two different diffraction angles in each psi angle from one incident X-ray beam, and to calculate the stress ; which is the most suitable to measure the actual stress under dynamic condition. Provided that it is necessary to count two diffraction profiles at onc … More e ; that causes necessity to develop the attachment and the system to connect two detectors. Originally, we planned to use an X-ray linear image sensor and also we developed the versatile X-ray diffractometer to attach various kinds of detectors and investigated the characteristics of each detector. Finally, it was too difficult to count with two linear image sensors, therefore we applied PSPC connected in series to dissolve the problem.Secondary, for the purpose to materialize the dynamic X-ray stress analysis, we planed X-ray stress measurement under rotational fatigue condition. At first, we developed X-ray stress analyzer utilizes SET method and succeeded to observe the actual stress change following to fatigue repetition increase by using cantilever-type rotational fatigue apparatus with loading gauge. It was made out newly that the actual stress before crack opening decreases with no relation to the stress amplitude, and after crack opening it decreases and breaks because of the stress releasing on the cracked surface. The result of our experience suggests to magnify the new applicable field for the X-ray stress analysis and contributes much to the next research work of material science. Less