Microscopic critical condition of hydrogen induced cracking based on hydrogen diffusion analysis at microscopic scale in dual phase steel

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K05977
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Materials/Mechanics of materials
• Research Institution: Osaka University
• Principal Investigator: MIKAMI Yoshiki 大阪大学, 接合科学研究所, 准教授 (40397758)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 水素割れ / 微視組織 / 数値解析

Outline of Final Research Achievements

Generally, metallic materials consist of multiple phase, and consequently, various properties are inhomogeneous. In this study, a numerical simulation model to calculate the microscopic distribution of stress and diffusible hydrogen concentration was proposed. The simulation method was applied to calculate the inhomogeneous distribution of the stress and diffusible hydrogen distribution at microscopic scale in the hydrogen cracking test. The characteristics of the distribution was in good agreement with the tendency of the observed cracks in the experiment. The approach is applicable to the evaluation of hydrogen cracking behavior of materials with multiple microstructure.

Free Research Field

溶接力学

Academic Significance and Societal Importance of the Research Achievements

既存の水素割れ限界評価は，導入した水素量と負荷応力を指標とした，「巨視的な」評価といえる．一方，多くの実用材料は複数の微視組織で構成され，不均一な応力および拡散性水素濃度分布によって割れが発生していると考えられる．本研究は，微視組織レベルの応力および拡散性水素濃度分布に基づいて水素割れ発生特性を議論しようとするものであり，本アプローチを発展させることで，耐水素割れ性に優れた材料の微視組織の特徴を提案することも可能になる．