A Novel 2d Analysis Method to Characterize Individual Grains Using High-energy X-ray Microbeam Diffraction

The design and development of new multiphase microstructures for specific technological applications require not only a characterization of the final microstructure, but also a detailed knowledge at the level of individual grains of the phase transformations taking place during the material processing. The availability of intense high-energy X-ray beams (50 to 300 keV) at a number of synchrotron sources has unlocked the door to unprecedented X-ray diffraction studies of a wide scope of processes in the bulk of the material [1–4]. Furthermore, the recent development of new optics components to focus the X-ray beam down to micro-dimensions [5], in combination with algebraic reconstruction techniques [6], has substantially increased the spatial resolution attainable in high-energy X-ray diffraction experiments. The state-of-the-art research in material science no longer aims at obtaining information about the average grain behavior, but at getting detailed information at the level of the ever smaller individual grains present in complex multiphase microstructures. The determination of the characteristics of individual micron-sized metastable austenite grains in the complex ferritic/bainitic/martensitic matrix of low-alloyed TRIP steels is a nice example of this trend and an example of great scientific and technological relevance [7,8].