Application of Hydrogen Micro-Imaging System for Quantitative Analysis of Hydrogen Behavior in Materials

本研究的目的是开发氢显微成像系统，用于定量分析氢在材料中的行为。为此，进行了放射发光法和放射自显影。在纯钒中，试样表面局部氢浓度与表面取向有关，即（001）晶向的氢浓度高于（111）晶向的氢浓度。这个实验使我们能够检查局部氢浓度和样品上的位置之间的关系。在V-Zr-Ni-Ti系BCC/Laves两相合金中，氢优先通过Laves相渗入试样。在该合金中，随着充氢时间的延长，在Laves相比例较高的区域，局部氢浓度逐渐降低，而在BCC相比例较高的区域，局部氢浓度先降低后升高。氢被认为移动到Laves相到BCC相。在体心立方（BCC）<95>结构的V_Fe_5合金中，Fe的加入提高了合金的吸氢速率，合金中氢的分布与Fe在凝固过程中形成的枝晶组织中的偏聚有关。实验定量地得到了局部区域氢浓度与铁浓度的关系。在体心立方结构的V_<35>Cr_<40>Ti_（1-x）<25>合金中，发现在凝固过程中热影响区氢的分布与钛有关，而在急冷区和缓冷区氢的分布与合金的组成元素没有明显的相关性。在这些区域中，氢的分布取决于枝晶结构的形态。

The purpose of the research is to develop hydrogen micro-imaging system for quantitative analysis of hydrogen behavior in materials. For this purpose, radioluminography and autoradiography was performed. In pure vanadium, local hydrogen concentration on the specimen surface depended on the surface orientation, that is, hydrogen concentration is higher at the grains with (001) crystal orientation compared with that with (111) orientation. This experiment enable us to examine a relation between the local hydrogen concentration and the position on the specimen. In the V-Zr-Ni-Ti alloy with BCC/Laves two phase structure, it was found that hydrogen preferentially penetrate into the specimen through the Laves phase. In this alloy, the local hydrogen concentration gradually decreased as the elapsed time after hydrogen charging at the region where higher ratio of the Laves phase, while the local hydrogen concentration decreased and then increased where higher ratio of the BCC phase. Hydrogen was thought to be moved to the Laves phase to the BCC phase. In the V_<95>Fe_5 alloy with BCC structure, it was found that the iron addition increases the hydrogen absorption rate, and that hydrogen distribution correlates with the iron segregation in the dendritic structure which formed during the solidification. In this experiment, the relation between the hydrogen concentration and iron concentration at the local area was obtained quantitatively. In the V_<35>Cr_<40>Ti_<25> alloy with BCC structure, it was found that hydrogen distribution correlates with titanium at the heat affected region during solidification, while hydrogen distribution has not clear correlation with the constituent element at the rapidly and slowly cooled region. In these regions, hydrogen distribution depended on the morphology of the dendritic structure.