Determination de contraintes residuelles en incidence rasante. Apport du rayonnement synchrotron

摘要

Using the brilliance, high intensity and parallelism of beams supplied by synchrotron radiation sources, residual stresses measurements have been performed 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 beam line at ESRF. It has been applied to stresses measurements on zirconia films grown on two zirconium alloys oxidized during an autoclave test. The oxide layers range from 0, 5 to 2, 5, μm. Using various incidence angles, different penetration thicknesses have been taken into account; we have studied by this mean the evolution of stresses as a function of depth. Some information related to crystallographic textures and content of tetragonal zirconia in the layers have also been derived from the X ray diffraction diagrams.