Evaluation of residual stresses in the bulk of materials by high energy synchrotron diffraction

High energy synchrotron diffraction is introduced as a new method for resid ual stress analysis in the bulk of materials. It is shown that energy dispe rsive measurements are sufficiently precise so that strains as small 10(-4) can be determined reliably. Due to the high intensity and the high paralle lism of the high energy synchrotron radiation the sample gauge volume can b e reduced to approximately 50 mu m x 1 mm x 1 mm compared to gauge volume o f one mm(3) up to several mm(3) achievable by neutron diffraction. The bene fits of the high penetration depth and the small gauge volume are demonstra ted by the results of stress studies performed on a fiber reinforced cerami c, a functional gradient material and a metal-ceramic compound. Furthermore , it is shown that in case of a cold extruded metal specimen the energy dis persive measurement technique yields simultaneous information about texture and residual stresses and thus allows a detailed investigation of elastic and plastic deformation gradients.