Evaluation of displacement and strain fields in weld solidification zone by in-situ observation using synchrotron radiation X-rays

Abstract

A method for evaluating the displacement and strain field of the solidification zone was developed that uses X-ray transmission images, which were obtained by high-brilliance synchrotron radiation. The developed method is aimed to be applied to time-series X-ray transmission images, for which it is difficult to evaluate displacement and strain fields using the general DIC (Digital Image Correlation) method and combines the evaluation of optical flow using the Lucas-Kanade method and the mapping technique to grid points using the Moving Least Squares (MLS) method. Furthermore, by applying this method to actual observations, it was shown that the microstructural state, temperature state, and strain state of each region can be evaluated simultaneously. By utilizing the developed evaluation method, it will be possible to understand the behavior of welds in the high temperature range, which has been difficult to understand in the past.