Professor Hiroyuki Toda and Assistant Professor Hiro Fujihara of the Department of Mechanical Engineering at Kyushu University, in collaboration with Assistant Professor Kyosuke Hirayama of the Graduate School of Engineering at Kyoto University (currently Associate Professor at the Faculty of Engineering and Design at Kagawa University), and Senior Scientists Akihisa Takeuchi and Masayuki Uesugi at SPring-8, have developed a multiscale, multidimensional, multimodal (3M) material evaluation technology. The developed technology combines X-ray CT with two levels of spatial resolution (high and low), with a special X-ray diffraction technique that rotates a sample while raster-scanning an X-ray beam focused to the micron level. By parallelly switching between three measurement and imaging methods, it is possible to conduct evaluation, analysis, and interpretation by focusing on a single test specimen.
The research group applied this technology on TRIP steel, a next-generation steel plate for automobiles. Changes in the material structure and damage behavior of the TRIP steel under external forces were evaluated with significantly higher accuracy and precision compared to existing material analysis methods. The researchers then identified material structural factors that define these phenomena and clarified material design guidelines to actively control nanoscale and microscale material structures to control the properties of the TRIP steel.
The 3M material evaluation technology can only be implemented at large synchrotron radiation facilities that can generate high X-ray energy and achieve high intensity of the rays using undulators. However, with the realization of SPring-8-II, it is expected that the technology will become more widely used to a certain extent. This is an achievement that will lead to the advancement of materials development, which is one of the Japan's strengths. The results of this research are published in Acta Materialia.
Journal Information
Publication: Acta Materialia
Title: Multimodal assessment of mechanically induced transformation and damage in TRIP steels using X-ray nanotomography and pencil-beam diffraction tomography
DOI: 10.1016/j.actamat.2024.120412
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