Abstract Abstract To achieve the goal of reducing greenhouse gas emissions and transitioning to a carbon-neutral To achieve the goal of reducing greenhouse gas emissions and transitioning to a carbon-neutral society, the transportation sector must focus on reducing the weight of vehicle bodies and improving society, the transportation sector must focus on reducing the weight of vehicle bodies and improving fuel efficiency through the use of high-strength steels. Advanced high-strength steels are being fuel efficiency through the use of high-strength steels. Advanced high-strength steels are being developed worldwide to improve fuel economy. However, overcoming hydrogen embrittlement developed worldwide to improve fuel economy. However, overcoming hydrogen embrittlement remains challenging. Hydrogen embrittlement is a phenomenon in which hydrogen is absorbed by remains challenging. Hydrogen embrittlement is a phenomenon in which hydrogen is absorbed by materials, making them brittle and prone to sudden failure. Research on hydrogen embrittlement has materials, making them brittle and prone to sudden failure. Research on hydrogen embrittlement has traditionally focused on materials used in harsh hydrogen environments. However, as the material traditionally focused on materials used in harsh hydrogen environments. However, as the material strength increases (tensile strength becomes higher than 1.2 GPa), the risk of hydrogen embrittlement strength increases (tensile strength becomes higher than 1.2 GPa), the risk of hydrogen embrittlement increases even in natural atmospheric environments. It is therefore necessary to improve the hydrogen increases even in natural atmospheric environments. It is therefore necessary to improve the hydrogen embrittlement properties of high-strength steels to enable their widespread use in commercial products. embrittlement properties of high-strength steels to enable their widespread use in commercial products. Understanding the relationship between the fracture behavior and microstructure is the key to retarding Understanding the relationship between the fracture behavior and microstructure is the key to retarding hydrogen-related premature fracture and improving the resistance to hydrogen embrittlement. hydrogen-related premature fracture and improving the resistance to hydrogen embrittlement. Crack morphology is an important characteristic; the crack surface area, crack discontinuity, and crack Crack morphology is an important characteristic; the crack surface area, crack discontinuity, and crack arrestability are closely related to the macroscopic mechanical properties. Although conventional 2D arrestability are closely related to the macroscopic mechanical properties. Although conventional 2D surface observation using SEM is appropriate for statistical analysis, it has some inevitable limitations surface observation using SEM is appropriate for statistical analysis, it has some inevitable limitations for analyzing the crack propagation behavior. On the other hand, non-destructive X-ray computed for analyzing the crack propagation behavior. On the other hand, non-destructive X-ray computed tomography using transmitted images is a useful method for analyzing the macroscopic 3D crack tomography using transmitted images is a useful method for analyzing the macroscopic 3D crack morphology and distribution of defects (scale: µm3–mm3). The combination of serial sectioning and morphology and distribution of defects (scale: µm3–mm3). The combination of serial sectioning and EBSD analysis allows for 3D microstructural / crystallographic characterization on a microscopic scale EBSD analysis allows for 3D microstructural / crystallographic characterization on a microscopic scale (scale: nm3–µm3). The local crack-arrestability and microstructural / crystallographic features of (scale: nm3–µm3). The local crack-arrestability and microstructural / crystallographic features of hydrogen-related fracture in high-strength as-quenched martensitic steel investigated by 3D multiscale hydrogen-related fracture in high-strength as-quenched martensitic steel investigated by 3D multiscale analysis will be presented in the lecture. analysis will be presented in the lecture. Distinguished Group Leader, Research Center for Structural Materials (RCSM) Distinguished Group Leader, Research Center for Structural Materials (RCSM) Hydrogen-related Fracture in high-strength MHydrogen-related Fracture in high-strength MNational Institute for Materials Science (NIMS) National Institute for Materials Science (NIMS) Session 1 ｜Akinobu Shibata is Distinguished Group Leader in Research Center for Structural Materials, National Institute for Materials Science (NIMS), Japan and Professor in Subprogram in Materials Science, Graduate Akinobu Shibata is Distinguished Group Leader in Research Center for Structural Materials, National School of Science and Technology, University of Tsukuba, Japan. He received his Ph.D from Department Institute for Materials Science (NIMS), Japan and Professor in Subprogram in Materials Science, Graduate of Materials Science and Engineering at Kyoto University in 2007. He worked at Tokyo Institute of School of Science and Technology, University of Tsukuba, Japan. He received his Ph.D from Department Technology (Assistant Professor (2007-2010)), Kyoto University (Assistant Professor (2010-2014) and of Materials Science and Engineering at Kyoto University in 2007. He worked at Tokyo Institute of Associate Professor (2014-2020), and then joined Research Center for Structural Materials at National Technology (Assistant Professor (2007-2010)), Kyoto University (Assistant Professor (2010-2014) and Institute for Materials Science since 2020. He also stayed at Mines ParisTech (France) as visiting Associate Professor (2014-2020), and then joined Research Center for Structural Materials at National researcher (2017-2018). His main research topics are microstructure evolution through phase Institute for Materials Science since 2020. He also stayed at Mines ParisTech (France) as visiting transformation, correlation between fracture behavior and microstructure, etc., in metallic materials, and researcher (2017-2018). His main research topics are microstructure evolution through phase transformation, correlation between fracture behavior and microstructure, etc., in metallic materials, and he currently focuses the study on hydrogen-related fracture of high strength steels. he currently focuses the study on hydrogen-related fracture of high strength steels. NIMS Award Symposium 2023Akinobu Shibata Akinobu Shibata Deformation and Fractureartensitic Steels artensitic Steels NIMS Talk S1-5 NIMS Talk S1-5 27
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