Stress distribution and tomographic profiling with energy dispersive x-ray scattering

Two novel and potentially powerful, x-ray scattering techniques for tomographic profiling of composite materials and for profiling residual strain variation, versus depth, in a specimen are presented. The techniques utilize a high intensity/energy "white" beam synchrotron source and monitor the energy dispersive scattering from a fixed micro-volume as the specimen is scanned through it. The tomographic profiles based on the net scattered intensity and exploiting absorption coefficient/scattering-power variations, can be contrast enhanced by selectively monitoring scattering from specific crystal structures in a composite material. The strain profiling technique is shown to chronicle the detailed internal the stress variation over several mm's of steel. The initial state residual stresses, the effect of a cantilever spring imposed external stress, and their interplay in elastic/plastic deformation are discussed.