Metallic Materials by means of Localized Hydrogen Distribution and Nanoscopic Damage Analyses

通过局部氢分布和纳米损伤分析的金属材料

基本信息

批准号：
12650084
负责人：
MINOSHIMA Kohji
金额：
$ 2.75万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650084/
关键词：
Environmental Strength Environmental Strength under Dynamic Loading Condition Hydrogen Embrittlement Thermal Description Spectroscopy of Hydrogen State of Hydrogen Crack Growth In situ Observation Atomic Force Microscopy 水素ぜい化水素局在化分布

项目摘要

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 hydrogen and nanoscopic in situ observation of the process of embrittlement by means of atomic force microscopy are applied; the thermal desorption spectroscopy analyze the state of hydrogen in the material, or hydrogen trap sites, and the responsible hydrogen in the material is correlated to hydrogen embrittlement. The hydrogen evolution rate of TiAl 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 an evolution peak at a … More 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 crack growth acceleration. The crack tip displacement (CTOD) of the embrittled crack is smaller than that of a fatigue crack in dry air, indicating that the embrittled crack has sharper crack than that of fatigue crack that is determined by the stress intensity factor. However the CTOD of the embrittled crack has large scatter band because the CTOD is influenced by the structure of the material and the localized hydrogen content in the material. The static SC crack grows in a steady manner in the order of urn without any retardation, when it grows along the grain boundary. However, the crack is reaching the triple grain boundary, the crack growth rate is decreasing with an increase in the CTOD. However, the crack passes over the triple grain boundary, the CTOD is decreased with an increase in the crack growth rate. When the cathodic current is applied, the crack path near the sample surface is transgranular, and the crack grows with a zigzag manner, and the crack grows with acceleration and retardation in the order of urn due to the amount of the localized hydrogen content in the material. Less

先进的金属材料对环境敏感，并为了阐明降解机制并改善服务环境中这些金属材料的韧性，我们必须阐明进入氢的过程以及材料中的氢气陷阱位点。在该研究项目中，采用原子力显微镜的氢和纳米镜原位观察氢和纳米镜的热解谱；热解吸光谱法分析了材料中氢的状态，或氢气陷阱位点，材料中的负责氢与氢的含量相关。 TIAL的氢进化速率通过阴极充电，较低的温度峰和较高的氢。较低温度下的峰与氢分解和从微结构缺陷（例如微型车）中的氢下降相关。由于收到的材料还显示出在……更高温度下的演化峰，并且演化速率几乎与阴极充电无关。此外，阴极充电提高了高于800℃的较高温度下的演化速率。这些氢被认为对裂纹生长加速有重要作用。包裹的裂纹的裂纹尖端位移（CTOD）小于干空气中疲劳裂纹的裂纹，表明包裹的裂纹比由应力强度因子确定的疲劳裂纹具有共享裂纹。然而，邻里裂纹的CTOD具有较大的散点带，因为CTOD受材料的结构和材料中局部氢含量的影响。当静态SC裂纹以urn的顺序稳定生长，而沿晶界生长时，静态裂纹就不会降低。但是，裂纹已达到三晶边界，随着CTOD的增加，裂纹的生长速率正在降低。但是，裂纹经过三重晶界，随着裂纹生长速率的增加，CTOD降低。当施加阴极电流时，样品表面附近的裂纹路径是跨粒状的，裂纹以锯齿状的方式生长，并且由于材料中局部氢含量的量，裂纹随着骨灰的加速和延迟而生长。较少的