Stress measurement method using X-ray diffraction

摘要

A stress of a c-axis-oriented specimen of a tetragonal polycrystal is measured using X-ray diffraction under the assumption of a plane stress state. An X-ray optical system is set in the location of phi=0°, 45° or 90°. An X-ray diffracted at a crystal plane (the direction of the normal thereto is the direction of an angle of psi) with the Miller indices (hkl) is detected. A diffraction angle theta in a strain state is measured in the vicinity of a Bragg's angle theta0 in a non-strain state. Strains epsilon with respect to a plurality of psi are calculated from the difference between the measurement values theta and the Bragg's angle theta0. Specific stress calculation formulae are determined with respect to the tetragonal system having the Laue symmetry 4/mmm. The stress is calculated from the slope of the linear line of plotted measurement results.