2022 Fiscal Year Final Research Report
Elucidation of hydrogen, vacancy, and plastic-strain related fracture phenomena in low-alloy steels by trans-scale analyses
| Project/Area Number |
19H02025
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Review Section |
Basic Section 18010:Mechanics of materials and materials-related
|
|---|
| Research Institution | Kyoto University of Advanced Science |
|---|
Principal Investigator |
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
武富 紳也 佐賀大学, 理工学部, 准教授 (20608096)
|
|---|
| Project Period (FY) |
2019-04-01 – 2023-03-31
|
| Keywords | 水素脆化 / 格子欠陥 / 原子シミュレーション / 力学特性 / 延性 / 鉄 |
|---|
| Outline of Final Research Achievements |
It has been shown that a lot of vacancy-type defects are locally nucleated at the prodromal stage of fracture of low-alloy steels under a hydrogen environment, and those defects have a strong correlation with embrittlement phenomena. In this study, we performed trans-scale analyses, which cross various scales, through the modeling of dislocation and vacancy by using electric- and atomistic-level simulations and Meso- and Macro-scale continuum methods. Especially, we revealed the aggregation and dissociation behavior of vacancies, and the influence of temperature and concentration on them. We also clarified the influence of hydrogen and vacancy on the dislocation motion, and then we discussed the relationship between the change in dislocation motion and the macroscopic embrittlement. Furthermore, we discovered a new vacancy transport mechanism toward grain boundaries and crack tips through the transition between vacancy clusters and prismatic-dislocation loops.
|
| Free Research Field |
材料力学
|
| Academic Significance and Societal Importance of the Research Achievements |
水素によって金属材料の延性が低下する水素脆化の研究は，その重要性から継続に行われてきたが未解明な部分が多い．このことが，水素を積極的に利用していくための一つの障壁になっている．本研究では，種々のシミュレーション手法に加えて，実験的なアプローチを援用することで，ミクロな欠陥への水素の作用と，マクロな脆化との関係を幅広く解明した．本研究の成果は，水素脆化による材料強度予測の高精度化や耐水素鋼の開発に向けて重要なものである．また，従来は全く知られていなかった格子欠陥の輸送現象を予測し，次なる研究の方向性まで示した．
|
