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Environmental Strength Evaluation and Investigation into Degradation Mechanisms of Advanced Metallic Materials based upon Analyses of State of Hydrogen and Nanofractography

Research Project

Project/Area Number 11450043
Research Category

Grant-in-Aid for Scientific Research (B).

Allocation TypeSingle-year Grants
Section一般
Research Field Materials/Mechanics of materials
Research InstitutionKYOTO UNIVERSITY

Principal Investigator

KOMAI Kenjiro  Graduate School of Engineering, KYOTO UNIVERSITY, Professor, 工学研究科, 教授 (70025948)

Co-Investigator(Kenkyū-buntansha) TANAKA Kazuto  Graduate School of Engineering, KYOTO UNIVERSITY, Research associate, 工学研究科, 助手 (50303855)
MINOSHIMA Kohji  Graduate School of Engineering, KYOTO UNIVERSITY, Associated Professor, 工学研究科, 助教授 (50174107)
Project Period (FY) 1999 – 2000
Project Status Completed (Fiscal Year 2000)
Budget Amount *help
¥14,900,000 (Direct Cost: ¥14,900,000)
Fiscal Year 2000: ¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 1999: ¥11,000,000 (Direct Cost: ¥11,000,000)
KeywordsEnvironmental Strength / Hydrogen Embrittlement / Thermal Desorption Spectroscopy of Hydrogen / Analyses of State of Hydrogen / Fatigue / Crack Growth / Intermetallic Compounds / Titanium Alloy / 高強度ステンレス鋼
Research Abstract

Advanced metallic materials are sensitive to an environment and in order to clarify the degradation mechanisms and to improve the toughness of these metallic materials in a service environment, we must clarify the process of hydrogen entry as well as the hydrogen trap sites in the material. In this research project, thermal desorption spectroscopy of hydrogens is applied to analyze the state of hydrogen in the material, or hydrogen trap sites, and correlate the responsible hydrogen in the material to hydrogen embrittlement : the materials investigated are titanium aluminides intermetallic compound and Ti-6Al-4V alloys, and the influence of environment on fatigue crack growth behavior was investigated. In the case of titanium aluminides, the tensile strength of the duplex material decreases in order of a water molecule content in an environment : the strength in vacuum is the highest, and decreases in order of laboratory air and water. In the case of the lamellar material, the fatigue c … More rack growth rate in dry air is higher in the R-C crack plane orientation than that in L-C crack plane orientation : the crack growth rate becomes higher when the crack grows as the lamellae are tearing off. However, in the case of the duplex material, the crack growth rate in the R-C crack plane orientation is smaller in low ΔK (ΔK_<off>) region. When the cathodic charging is applied, the fatigue crack growth rate becomes higher than that in dry air, in particular at higher stress intensity factor range. The hydrogen evolution rate is increased by cathodic charging, with lower temperature peaks and higher ones. The peaks at lower temperatures are correlated with hydrides decomposition and detrapping of hydrogen from microstructural imperfections such as microvoids. As received materials also shows a evolution peak at a higher temperature, and the evolution rate is almost independent of cathodic charging. In addition, the evolution rate at a higher temperature above 800℃ is increased by cathodic charging. These hydrogens are considered to have an important role on fatigue crack growth acceleration. In contrast with these, the crack growth rate of Ti-6Al-4V alloy is sensitive to environment when the crack plane orientation is T-L, whereas the crack growth rate in a solution is almost equal to that conducted in dry air. However, the crack path changes towards the longitudinal direction, when the applied stress intensity factor range exceeds a certain value. The hydrogen evolution kinetics are independent of the testing environment, or the acceleration of crack growth, and the mechanisms of the crack acceleration are discussed. Less

Report

(3 results)
  • 2000 Annual Research Report   Final Research Report Summary
  • 1999 Annual Research Report
  • Research Products

    (11 results)

All Other

All Publications (11 results)

  • [Publications] 駒井謙治郎: "TiAlの疲労き裂進展特性に及ぼす試験片方位と水環境の影響"第10回破壊力学シンポジウム講演論文集. 158-161 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] 駒井謙治郎: "Ti-6Al-4V合金の腐食疲労き裂進展特性に及ぼす材料異方性の影響"日本機械学会関西支部第76期定時総会講演会講演論文集. No.04-1. 7-1-7-2 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] 箕島弘二: "金属間化合物TiAlの疲労き裂進展に及ぼす環境効果と昇温水素分析"日本機械学会M&M2001材料力学部門講演会. (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] K.Minoshima: "Influence of Environment on Fatigue Crack Growth in Titanium Aluminides and Hydrogen Evolution Behaviour Evaluated by Thermal Desorption Spectroscopy"Fatigue & Fracture of Engineering Materials and Structures.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] K.Komai, M.Minoshima, and K.Obara: "The Influence of Crack Plane Orientation and Water on Fatigue Crack Growth in TiAl Intermetallic Compounds"Proceeding of the 10th Symposium on Fracture and Fracture Mechanics, Society of Materials Science, Japan. 158-161 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] K.Komai, M.Minoshima and K.Shiho: "Influence of Anisotropy on Corrosion Fatigue Crack Growth Behavior of Ti-6Al-4V Alloy"Proceeding of The 1St Symposium on micromaterials, The Society of Materials Science Japan. 41-42 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] M.Minoshima, K.Obara, N.Minamino and K.Komai: "The Effects of Environment on Fatigue Crack Propagation and Thermal Desorption Spectroscopy in TiAl Intermetallic Compounds"To be presented at the 2001 Annual Meeting of JSME/MMD, Japan Society of Mechanical Engineers. (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] K.Minoshima, K.Obara, N.Minamino and K.Komai: "Influence of Environment on Fatigue Crack Growth in Titanium Aluminides and Hydrogen Evolution Behavior Evaluated by Thermal Desorption Spectroscopy"Submitted to Fatigue & Fracture of Engineering Materials and Structures. (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] 駒井謙治郎: "Ti-6Al-4V合金の腐食疲労き裂進展特性に及ぼす材料異方性の影響"日本機械学会関西支部第76期定時総会講演会講演論文集. No.04-1. (2001)

    • Related Report
      2000 Annual Research Report
  • [Publications] 箕島弘二: "金属間化合物TiAlの疲労き裂進展に及ぼす環境効果と昇温水素分析"日本機械学会M&M2001材料力学部門講演会. (2001)

    • Related Report
      2000 Annual Research Report
  • [Publications] 駒井謙治郎: "TiAl の疲労き裂進展特性に及ぼす試験片方位と水環境の影響"第10回破壊力学シンポジウム講演論文集. 158-161 (1999)

    • Related Report
      1999 Annual Research Report

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Published: 1999-04-01   Modified: 2016-04-21  

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