Determination of the dominant defects of hydrogen embrittlement in iron-based materials through the development of in-situ measurement methods of atomic vacancies
| Project/Area Number |
18K13980
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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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) |
2018-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2018: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Keywords | 格子欠陥 / 放射線 / 陽電子 / 水素脆化 / 鉄 / ステンレス鋼 / hydrogen embrittlement / defect / vacancy / hydrogen / iron / stainless steel / positron annihilation / defects / vacancy clusters |
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| Outline of Final Research Achievements |
The purpose of this study is to identify the primary defects of hydrogen embrittlement in pure iron and austenitic stainless steels by positron annihilation spectroscopy, the only non-destructive technique for the detection of atomic vacancies with high sensitivity. Given the high hydrogen and monovacancy diffusivity at room temperature, to detect the defects originally induced by hydrogen stress was applied in a hydrogen environment followed by temperature-variable measurements or in-situ analysis. The results suggested that monovacancies were stabilized by hydrogen trapping in hydrogen-embrittled pure iron, indicating for the first time that the dominant defects of hydrogen embrittlement are vacancy-hydrogen complexes. In austenitic stainless steel, mono-vacancy-level defects stabilized by binding to hydrogen were detected. The critical factor of the hydrogen embrittlement was ascribed to the accumulation of small vacancy clusters in high-density in high-strain regions.
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| Academic Significance and Societal Importance of the Research Achievements |
水素環境下での鉄系材料の力学特性の劣化という水素脆化の機構は未解明であり，水素社会に向けての課題の一つである。本研究では，純鉄およびオーステナイト系ステンレス鋼の水素脆化支配欠陥を陽電子消滅法により明らかにした。本研究の結果は学術的には長年未解明であったこの機構解明に資した。この結果の学術的・工業的波及効果も大きいで、最終的に水素社会を迎える時代に対応する鋼材の開発するように、耐水素ステンレス鋼の基本的な設計ガイドラインを提供することが期待される。
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Report
(4 results)
Research Products
(35 results)
