The use of high energy X-rays from the Advanced Photon Source to study stresses in materials

High-energy X-rays from third-generation synchrotron sources are opening new opportunities for the studies of stresses in materials. At the Advanced Photon Source (APS) 1-ID beamline, the combination of an undulator and specialized high-energy X-ray optics produces a very brilliant photon beam in the 50-100 keV energy range. In this paper, three experiments using this capability are described. In the first the combined effects of residual and applied strain on the austenite and ferrite phases are measured in a duplex steel during deformation. The austenite is seen to yield prior to the ferrite. In the second experiment, high-energy, small-angle scattering (HE-SAXS) and wide-angle scattering (WAXS) were used to study a thermal barrier coating. This allowed information to be obtained on the directionality of the pores in this material, as well as on gradients in the crystallographic texture and phase composition. In the final experiment, the behavior of an individual grain of an aluminum alloy was tracked during deformation using a 3-D X-ray microscope. This is the first phase of a project in which we intend to measure many more individual grains to deduce statistically significant effects of grain size, grain orientation, and effect of neighboring grains during deformation processes. The paper also briefly comments on possible future developments for high-energy X-ray sources.