| Project/Area Number |
21K04627
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 26010:Metallic material properties-related
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| Research Institution | Chiba University |
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Principal Investigator |
Chiari Luca 千葉大学, 大学院工学研究院, 助教 (20794572)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2023: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2022: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2021: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Keywords | 水素脆化 / 格子欠陥 / 陽電子消滅法 / 鉄 / ニッケル / 空孔型欠陥 / 金属 / その場測定 / 陽電子 |
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| Outline of Research at the Start |
The elucidation of the hydrogen embrittlement mechanism in hydrogen-susceptible metallic materials is a prerequisite for the safe use and development of structural materials, such as stainless steels, in the hydrogen transport and storage infrastructure in the advent of the upcoming hydrogen society.
In this research, we aim to detect and identify the primary atomic defects responsible for the hydrogen embrittlement process by devising and developing innovative approaches to positron annihilation spectroscopy, which is the only techniques for detecting atomic vacancies.
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| Outline of Final Research Achievements |
The primary scope of this research is to determine the lattice defects responsible for hydrogen embrittlement in metallic materials by in-situ measurements in a hydrogen environment and under tensile stress. A new experimental system was developed to enable positron lifetime measurements under tensile stress and while charging hydrogen. In pure iron strained under conditions of high hydrogen susceptibility, the formation of vacancy-hydrogen complexes during hydrogen addition and their growth into vacancy clusters by aging in air was observed for the first time.
In addition, the formation and time dynamics of hydrogen-induced defects in pure nickel was measured by high-speed positron lifetime measurements. Vacancy-hydrogen complexes were found to form just by hydrogen addition without tensile stress. By room temperature aging, they gradually disappeared and the remaining monovacancies became mobile and agglomerated into vacancy clusters, which progressively increased in size.
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| Academic Significance and Societal Importance of the Research Achievements |
金属材料の水素脆化は，水素環境下における力学特性の低下や遅れ破壊現象であり，水素社会を迎えるにあたり解決すべき重要な課題となっている。本研究は，純鉄および純ニッケルにおける空孔-水素複合体の形成を実証し，室温時効によるその成長過程を観察した初めての研究である。この結果は，学術的には長年未解明であった水素脆化の原子レベルメカニズムの解明に貢献したものであり，学術的・工業的大きな波及効果をもたらすことが期待される。最終的には，本研究で得られた新たな知見は，水素社会に向けて耐水素鋼材の開発につながる可能性がある。
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