The effect of stress rate on hydrogen embrittlement mechanisms and the construction of quantitative evaluation on the characteristic of hydrogen embrittlement

Research Project

Project/Area Number	16K17976
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Multi-year Fund
Research Field	Materials/Mechanics of materials
Research Institution	Shonan Institute of Technology
Principal Investigator	Ohmi Toshihito 湘南工科大学, 工学部, 講師 (90586489)
Project Period (FY)	2016-04-01 – 2018-03-31
Project Status	Completed (Fiscal Year 2017)
Budget Amount *help	¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000) Fiscal Year 2017: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000) Fiscal Year 2016: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Keywords	水素脆化 / 数値解析 / ひずみ速度 / 疲労 / 材料強度
Outline of Final Research Achievements	In this study, the effect of stress rate on hydrogen concentration behavior under cyclic loading condition was clarified by numerical analyses and fatigue tests of hydrogen charged specimen. The following results were obtained. 1) The numerical analysis for the effect of stress rate on hydrogen diffusion and concentration behavior under cyclic loading condition was conducted. From this analysis, the effect of stress rate on work hardening has no influence on hydrogen concentration behavior. And the possibility that hydrogen concentration capacity can be estimated by the triaxial factor was indicated. 2) Fatigue tests of hydrogen charged specimen were conducted. From these results, a change of crack growth behavior was found by loading rate. This result indicates a possibility that hydrogen embrittlement mechanism depends on stress rate.