Enhancement of Fatigue Damage due to Environmental Variation and its Recovery Treatment

环境变化引起的疲劳损伤的加剧及其恢复处理

• 批准号: 13450262
• 负责人: NAGUMO Michihiko
• 金额: $ 9.15万
• 依托单位: Waseda University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13450262/
• 关键词: Hydrogen embrittement; fatigue; Delayed fracture; Environmental failure; Transmission electron, microsocpy; Electan diffraction; High strength steel; Bio-medical materials; 力学物性; 格子欠陥; 強度; 破壊; 応力腐食割れ; 生体・福祉材料; 高強度鋼; 点欠陥; 原子空孔; 表面反応

Fatigue properties of steel are strongly affected by environmental conditions, in which hydrogen plays an essential role. The clarification of the mechanism and measures for reducing the susceptibility have been subjects of many studies. We have proposed a new model for hydrogen embrittlement of steel that claims enhanced formation of vacancies during plastic deformation with the aid of hydrogen and the coagulation of vacancies that leads to the decrease in the ductile crack growth resistance. Based on the model, the aim of the present studies is to investigate particularly die effect of variations of environmental conditions on the susceptibility to hydrogen-related feilure. Firstly, defects created during fatigue have been detected using hydrogen as a probe, revealing the formation of vacancies as a fector of fetigue damage. Interactions between fatigue damage and hydrogen result in degradation of fatigue properties and enhanced susceptibility to hydrogen-related failure. On the same … More basis, in a delayed fracture test of a high strength steel cyclic variations of the applied stress and hydrogen-charging current density and their synergetic effect have been confirmed to enhance the susceptibility. Annealing of pre-fatigued specimens at temperatures as low as 200℃ recovered the enhancement of the susceptibility. Evolution of hydrogen-related failure in a biomedical material, a shape-memory NiTi alloy that is uses in oral cavity, has been revealed. The proposed model has been directly proved with transmission electron microscopy using specimens fabricated by means of a focused ion beam method from just beneath fracture surface. Crack growth associated with local amorphization has been revealed, supporting the increased density of vacancies. Hydrogen microprint technique has been also applied for revealing local distribution of defects that trap hydrogen. Dynamic observation of electron diffraction has been successfully applied for revealing the surface structure of specimens in nanometer-scale. Less

钢的疲劳性能受环境条件的强烈影响，其中氢起着至关重要的作用。阐明降低易感性的机制和措施一直是许多研究的主题。我们提出了一个新的模型，要求加强形成的空位在塑性变形过程中的帮助下，氢和空位的凝固，导致韧性裂纹扩展阻力的下降钢的氢脆。在此基础上，着重研究了环境条件变化对氢致疲劳敏感性的影响。首先，在疲劳过程中产生的缺陷已被发现使用氢作为探针，揭示了空位的形成作为疲劳损伤的一个因素。疲劳损伤和氢之间的相互作用导致疲劳性能的劣化和对氢相关失效的敏感性增强。在同一 ...更多信息 在此基础上，在高强度钢的延迟断裂试验中，证实了外加应力和充氢电流密度的循环变化及其协同效应会提高敏感性。预疲劳试样在低至200℃的温度下退火，恢复了磁化率的提高。揭示了一种生物医用材料--口腔用形状记忆镍钛合金氢致失效的演化规律。所提出的模型已被直接证明与透射电子显微镜使用标本制造的聚焦离子束方法从下面的断裂表面。与局部非晶化相关的裂纹扩展已经被揭示，支持空位密度的增加。氢微印技术也被应用于揭示捕获氢的缺陷的局部分布。电子衍射动态观察已成功地应用于揭示纳米尺度的样品表面结构。少

项目成果

M. Nagumo, S. Sekiguchi, H. Hayashi, K. Takai: "Enhanced susceptibility to delayed fracture in pre-fatigued martensitic steel"Materials Science and Engineering A. A344. 86-91 (2003)

M. Nagumo、S. Sekiguchi、H. Hayashi、K. Takai：“预疲劳马氏体钢延迟断裂的敏感性增强”材料科学与工程 A. A344。

T. Yamaguchi and M. Nagumo: "Simulation of Hydrogen Thermal Desorption under Reversible Trapping by Lattice Defects"ISIJ International. 43. 514-519 (2003)

T. Yamaguchi 和 M. Nagumo：“晶格缺陷可逆捕获下氢热脱附的模拟”ISIJ International。

志村弘樹, 茶谷隆, 南雲道彦, 林博昭: "マルテンサイト鋼の疲労における点欠陥の生成"材料とプロセス. 15. 572 (2002)

Hiroki Shimura、Takashi Chatani、Michihiko Nagumo、Hiroaki Hayashi：“马氏体钢疲劳过程中点缺陷的产生”材料和工艺 15. 572 (2002)。

M.Nagumo, S.Sekiguchi, H.Hayashi, K.Takai: "Enhanced susceptibility to delayed fracture in pre-fatigued martensitic steel"Materials Science and Engineering A. A344. 86-91 (2003)

M.Nagumo、S.Sekiguchi、H.Hayashi、K.Takai：“预疲劳马氏体钢延迟断裂的敏感性增强”材料科学与工程 A. A344。

T.Yamaguchi, M.Nagumo: "Simulation of Hydrogen Thermal Desorption under Reversible Trapping by Lattice Defects"ISIJ International. 43. 514-519 (2003)

T.Yamaguchi、M.Nagumo：“晶格缺陷可逆捕获下氢热脱附的模拟”ISIJ International。