Elucidation of hydrogen embrittlement mechanism of functional materials with nanostructure and development of new methods of inhibiting destruction

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K03862
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 18010:Mechanics of materials and materials-related
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Nishimura Kenji 国立研究開発法人産業技術総合研究所, エレクトロニクス・製造領域, 主任研究員 (20357718)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 分子動力学 / 水素脆化 / 水素拡散 / 転位 / 水素化物 / 水素濃度 / 材料強度

Outline of Final Research Achievements

The hydrogen embrittlement mechanism of palladium used for hydrogen separation membranes was investigated using atomic-scale simulations. We focused on hydrogen diffusion and fracture phenomena that occur on a nanoscale starting from palladium hydrides. We found that the state of the palladium hydrides remarkably depends on the hydrogen concentration and has a great influence on hydrogen embrittlement. Our simulations revealed that the tensile strength significantly decreases due to the presence of initial interfacial dislocations in the two-phase coexistence state of α phase and β phase. Furthermore, it was also found that the two-phase coexistence state is eliminated in the nanocrystal. It was suggested that nanocrystallization of palladium increase the durability of the hydrogen separation membranes.

Free Research Field

機械工学

Academic Significance and Societal Importance of the Research Achievements

水素利用機器の安全性において、水素を吸収することにより材料の強度が低下する水素脆化は長年の課題である。本研究の特色は、水素脆化に関する研究がほとんど行われていないパラジウムなどの機能材料の水素脆化メカニズムに注目した点である。パラジウムの水素脆化は水素化物に起因しており、水素濃度と水素化物の関係および水素濃度が材料強度に及ぼす影響について重要な知見が得られた。水素脆化メカニズムの解明により、部材の信頼性を向上させると同時に新規材料開発のための材料設計指針が得られる。