Determination of residual stresses in grazing incidence - Synchrotron radiation

Using the brilliance, high intensity and parallelism of beams supplied by s ynchrotron radiation sources, residual stresses measurements have been perf ormed on very thin films. The experiment consists in maintaining the X ray beam in grazing incidence and driving the detector and sample movements so as to scan the Bragg reflexion of (hkl) planes with given tilt and azimuth. The method has been worked up on the multitechnic goniometer of the IF bea mline at ESRF. It has been applied to stresses measurements on zirconia fil ms grown on two zirconium alloys oxidized during an autoclave test. The oxi de layers range from 0,5 to 2,5 mum. Using various incidence angles, differ ent penetration thicknesses have been taken into account; we have studied b y this mean the evolution of stresses as a function of depth. Some informat ion related to crystallographic textures and content of tetragonal zirconia in the layers have also been derived from the X ray diffraction diagrams.