Validation of hydrogen embrittlement model based on quantitative evaluation of vacancy-type defects using computational methods

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K05069
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26040:Structural materials and functional materials-related
• Research Institution: Japan Atomic Energy Agency
• Principal Investigator: Ebihara Kenichi 国立研究開発法人日本原子力研究開発機構, システム計算科学センター, 研究主幹 (40360416)
• Co-Investigator(Kenkyū-buntansha): 鈴土 知明 国立研究開発法人日本原子力研究開発機構, システム計算科学センター, 再雇用職員 (60414538) ; 松本 龍介 京都先端科学大学, 工学部, 准教授 (80363414)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 水素脆化 / 水素助長ひずみ誘起空孔モデル / 昇温脱離スペクトル / き裂進展挙動 / 反応拡散方程式 / 分子動力学 / 機械学習ポテンシャル / 空孔型欠陥

Outline of Final Research Achievements

To validate the hydrogen-enhanced strain-induced vacancy model as one of the mechanisms of hydrogen embrittlement, the interaction of hydrogen with vacancies and vacancy clusters was evaluated by molecular statics, incorporated into the hydrogen reaction-diffusion equation considering the behavior of vacancies and vacancy clusters, and the thermal desorption spectrum of hydrogen from pure iron containing hydrogen-enhanced strain-induced vacancies was simulated under the experimental conditions. In this calculation, assuming a vacancy formation of about 1.2e-6 was necessary. Molecular dynamics simulations using a machine-learning potential reproduced the experimental trend that {100} plane cracks are more likely to occur than {110} plane cracks, which have the lowest surface energy, and clarified the mechanism.

Free Research Field

計算材料科学

Academic Significance and Societal Importance of the Research Achievements

本研究の結果は、今後さらに発展させることで、空孔型欠陥と脆性との相間に関する定量的な議論及び水素助長ひずみ誘起空孔モデルの定量的評価を可能とし、水素誘起損傷（主に空孔型欠陥）を回復させる最適な焼鈍条件の確立や水素貯蔵タンクなどの水素社会のインフラに必要な耐水素脆化材料の開発に貢献可能と考える。