Crystallographic and lattice defect analyses beneath hydrogen embrittlement fracture surface under local- and atomic-level toward new evaluation method

• Project/Area Number: 18H01740
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 26040:Structural materials and functional materials-related
• Research Institution: Sophia University
• Principal Investigator: Takai Kenichi 上智大学, 理工学部, 教授 (50317509)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥17,680,000 (Direct Cost: ¥13,600,000、Indirect Cost: ¥4,080,000); Fiscal Year 2020: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000); Fiscal Year 2019: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2018: ¥11,050,000 (Direct Cost: ¥8,500,000、Indirect Cost: ¥2,550,000)
• Keywords: 水素脆性 / 高強度鋼 / 水素 / 破壊 / 格子欠陥

Outline of Final Research Achievements

Local areas near hydrogen embrittlement fracture surface of high strength steels has been analyzed to clarify the nature at atomic-level such as vacancies, dislocation and grain boundary on the bases of crystallographic and lattice defect aspects. As a results, dislocations and vacancies were formed in quasi-cleavage fracture area as a fracture initiation. In contrast, they were not formed in intergranular fracture area as a fracture propagation area.

Academic Significance and Societal Importance of the Research Achievements

自動車用材料を始め、機械・構造材料は応力を負荷されながら使用され、かつ、腐食環境・高圧水素環境など過酷な条件下で使用されるため、ある時間経過後に突然破壊する水素脆化が懸念されてきた。これまで、この水素脆化に関して、様々な機構が提唱されてきたが、必ずしも統一した見解に至っていない問題点があった。そこで本研究では、従来の試験片全体の平均情報を解析する手法から脱却し、水素脆化破面直下の局所領域を解析することで、水素脆化破壊の本質に迫る知見が得られた。これらの知見は、今後の水素脆化評価方法の提案、さらには水素脆化特性に優れた材料設計指針に展開可能である。

Research Products

• [Journal Article] Hydrogen Desorption Behavior Trapped in Various Microstructures of High-Strength Steels Using Thermal Desorption Analysis (2020)
  • Author(s): Saito Kei、Takai Kenichi
  • Journal Title: Metallurgical and Materials Transactions A Volume: 52 Issue: 2 Pages: 531-543
  • DOI: 10.1007/s11661-020-06096-2
• [Journal Article] Hydrogen Embrittlement Susceptibility Evaluation of Tempered Martensitic Steels Showing Different Fracture Surface Morphologies (2019)
  • Author(s): Kippei OGAWA, Yu MATSUMOTO, Hiroshi SUZUKI and Kenichi TAKAI
  • Journal Title: ISIJ International Volume: 59 Issue: 9 Pages: 1705-1714
  • DOI: 10.2355/isijinternational.ISIJINT-2019-130
  • NAID: 130007706764
  • ISSN: 0915-1559, 1347-5460
  • Year and Date: 2019-09-15
  • Peer Reviewed / Open Access
• [Journal Article] Hydrogen Desorption Spectra from Excess Vacancy-Type Defects Enhanced by Hydrogen in Tempered Martensitic Steel Showing Quasi-cleavage Fractur (2019)
  • Author(s): KEI SAITO, TETSUYA HIRADE, and KENICHI TAKAI
  • Journal Title: METALLURGICAL AND MATERIALS TRANSACTIONS A Volume: 50A Issue: 11 Pages: 5091-5102
  • DOI: 10.1007/s11661-019-05450-3
  • Peer Reviewed / Open Access
• [Journal Article] Hydrogen Embrittlement Susceptibility Evaluation of Tempered Martensitic Steels Showing Different Fracture Surface Morphologies (2019)
  • Author(s): Ogawa Kippei、Matsumoto Yu、Suzuki Hiroshi、Takai Kenichi
  • Journal Title: Tetsu-to-Hagane Volume: 105 Issue: 1 Pages: 112-121
  • DOI: 10.2355/tetsutohagane.TETSU-2018-107
  • NAID: 130007599133
  • ISSN: 0021-1575, 1883-2954
  • Peer Reviewed
• [Journal Article] Hydrogen behavior in high strength steels during various stress applications corresponding to different hydrogen embrittlement testing methods (2018)
  • Author(s): Matsumoto Yu、Miyashita Tomonori、Takai Kenichi
  • Journal Title: Materials Science and Engineering: A Volume: 735 Pages: 61-72
  • DOI: 10.1016/j.msea.2018.08.002
  • Peer Reviewed / Open Access
• [Journal Article] Change in dislocation mobility of tempered martensitic steel through charged hydrogen (2018)
  • Author(s): Kamei H、Matsumoto Y、Suzuki H、Takai K
  • Journal Title: IOP Conference Series: Materials Science and Engineering Volume: 461 Pages: 012034-012034
  • DOI: 10.1088/1757-899x/461/1/012034
  • Peer Reviewed / Open Access
• [Journal Article] Changes in the substructure of tempered martensitic steel during the application of cyclic elastic stress in the presence of hydrogen (2018)
  • Author(s): Ohori M、Chiba T、Matsumoto Y、Suzuki H、Takai K
  • Journal Title: IOP Conference Series: Materials Science and Engineering Volume: 461 Pages: 012062-012062
  • DOI: 10.1088/1757-899x/461/1/012062
  • Peer Reviewed / Open Access
• [Presentation] 熱負荷による高強度鋼中の非拡散性水素の状態変化と脆化感受性への影響 (2021)
  • Author(s): 奥野 一樹、高井 健一
  • Organizer: 日本鉄鋼協会第181回春季講演大会
• [Presentation] 水素添加有無で繰り返し応力を負荷した焼戻しマルテンサイトの水素脆化感受性比較 (2020)
  • Author(s): 菊地慶祐、大堀正晴、千葉隆弘、高井健一
  • Organizer: 日本鉄鋼協会第180回秋季講演大会
• [Presentation] TOPOGRAPHIC AND CRYSTALLOGRAPHIC ANALYSES OF HYDROGEN-RELATED FRACTURE SURFACES IN NOTCHED TEMPERED MARTENSITIC STEEL (2020)
  • Author(s): M. Zakuan, K. Takai, K. Iwanaga, T. Okamura and N. Tanaka
  • Organizer: COM 2020
  • Int'l Joint Research
• [Presentation] 焼戻しマルテンサイト鋼における水素起因割れの起点部/進展部近傍の格子欠陥解析 (2019)
  • Author(s): 千葉隆弘，安川昂志 ，高井健一
  • Organizer: 日本鉄鋼協会第178回秋季講演大会
• [Presentation] 焼戻しマルテンサイト鋼の水素起因割れにおけるき裂の起点・進展挙動解析 (2019)
  • Author(s): 千葉隆弘，安川昂志 ，高井健一
  • Organizer: 日本鉄鋼協会第178回秋季講演大会
• [Presentation] States of hydrogen and hydrogen embrittlement of high-strength steels (2019)
  • Author(s): Kenichi Takai
  • Organizer: CORROSION OIL&GAS 2019
  • Int'l Joint Research / Invited
• [Presentation] Crystallographic analysis and hydrogen-enhanced lattice defect evaluation beneath hydrogen-related fracture surface of high-strength steels (2019)
  • Author(s): Kenichi Takai
  • Organizer: DSL2019
  • Int'l Joint Research
• [Presentation] Crystallographic analysis and hydrogen-enhanced lattice defect evaluation beneath hydrogenrelated fracture surface of highstrength steels (2019)
  • Author(s): Kenichi Takai
  • Organizer: HYDROGENIUS, I2CNER AND HYDROMATE JOINT RESEARCH SYMPOSIUM
  • Int'l Joint Research / Invited
• [Presentation] Hydrogen trapping sites and hydrogen embrittlement of iron and steels (2018)
  • Author(s): Kenichi Takai
  • Organizer: Thermec 2018
  • Int'l Joint Research / Invited
• [Presentation] Hydrogen trapping sites and hydrogen embrittlement of iron and steels (2018)
  • Author(s): Kenichi Takai
  • Organizer: ISOPE-2018
  • Int'l Joint Research / Invited
• [Presentation] Trapping states of hydrogen and hydrogen embrittlement of high strength steels (2018)
  • Author(s): Kenichi Takai
  • Organizer: ECF22
  • Int'l Joint Research / Invited