Synchrotron Computer Tomography as a Characterization Method for Engineering Materials

Abstract

X-ray tomography is a non-destructive imaging technique enabling a three-dimensional representation of the irradiated volume, its internal architecture and subsequently a qualitative and quantitative evaluation of materials. It is thus an attractive method for examinations in the field of materials science, where the correlation between macroscopic properties and microstructure often is of major interest. In particular, tomography using high-energy synchrotron radiation is well suited for the examination of metallic materials due to its high penetrationdepth. In addition to absorption contrast, the (partial) coherence of a synchrotron beam also allows the utilization of phase contrast for imaging techniques [1]. The achievable spatial resolution using synchrotron beams may also be higher than that of conventional laboratory(-based) X-ray tomography using focusing optics [2].There are about fifty synchrotrons worldwide. The high brilliance achieved by third-generation facilities, such as ESRF in Grenoble, France [3] and Petra III/DESY in Hamburg, Germany [4] enables experiments in real time with recording times of up to a few MHz frame rates at selected beamlines [5]. Another benefit is the adjustability of the monochromatic beam to suitable energies for specific experiments/materials or for absorption edge tomography as well as the possible combination with other experimental methods directly at the beamline, e. g. diffraction. It is extremely difficult to give an up-to-date overview of the available energy ranges, achievable minimum voxel sizes and scanning times on synchrotron beamlines with tomographic setups suitable for 3D imaging of metallic structures due to the highly dynamic method development; orientational overviews can be found in [2, 6]. This paper will provide a summary of current methods and applications of synchrotron tomography and practical examples taken from current research topics covered by the authors.