火电厂、核电厂都要使用大量的承温、承压结构部件，电厂运行中需要使用大量的高温高压水作为冷却剂和能量传递介质，在高温高压水或辐照环境下，结构部件通常会受到氢致损伤的影响。即使在非高温高压或无辐照计量条件下，结构部件也会受到环境氢脆、氢蚀等的影响，对结构部件氢致损伤问题的研究既有现实意义也有理论价值。本文从宏观实验、宏观和微观观测以及原子尺度数值模拟几个方面对铁基材料氢致损伤的现象和机理进行了分析。在宏观尺度，我们应用小冲孔实验方法对一种核电工业中广泛应用的高强度钢材料的氢致损伤特性进行研究。我们按照小冲孔实验方法的原理制备小圆片试样，采用不同电流强度对小圆片试样进行电解充氢。对充氢后的试样开展宏观力学实验，并用扫描电子显微镜对失效试样的断裂表面进行观测和分析。结果发现在电流强度逐渐增大的条件下，试样断裂表面形貌随之由韧性断裂演变为脆性断裂的特性，即材料脆性逐渐增强。通过理论分析，得到试样内部氢的浓度随着电流强度的增大而升高的结论。综合实验和理论分析的结论可知，铁基材料内部的氢使材料机械性能降低；随着内部氢含量升高，材料脆性增强。这些结论使得我们对氢脆的现象有了更多的认识。考虑到想要进一步理解氢致损伤的机理需要从微观尺度入手，我们选择分子动力学方法对BCC铁的氢致损伤特性进行研究。首先采用了一个应用效果较好的EAM势函数，对其进行离散化得到势函数文件，进而应用该势函数对BCC单晶铁的氢致损伤问题进行模拟分析。研究了一系列重合位置点阵类型的晶界，计算其晶界能，并根据结果选取了一组特别关注的晶界作为BCC双晶铁氢致损伤问题的研究对象。基于以上原子尺度的模拟的结果，对BCC铁氢致损伤机理进行了探讨。发现对于BCC单晶和双晶铁，氢致损伤或者说氢脆现象主要由两种机制共同作用，即氢致脱粘（hydrogen-enhanced decohesion）理论，也被称为晶格脆化理论，以及氢致局部塑性（hydrogen enhanced localized plasticity）理论。

Large amounts of structural components bearing high-temperature and/or high-pressure are used in thermal power plants and nuclear power plants, since the operation of a power plant needs to use high-temperature and high-pressure water as a coolant and the working fluid of energy transferring. Serving in the high-temperature and high-pressure water or irradiation conditions, structural components usually are under the influence of hydrogen-induced damage. Even if the structural components are serving in the environment without high-temperature and high-pressure water or irradiation, the influence of hydrogen embrittlement and hydrogen attack will still need to be considered. Therefore, the research on hydrogen-induced damage of structural components is of profound theoretical and practical significance. In the current dissertation, the phenomenon and mechanism of hydrogen-induced damage of iron-based material was studied from the perspective of macroscopic experiments, macroscopic and microscopic observation and atomic-scale numerical simulation.On a macroscopic scale we studied the characteristics of hydrogen-induced damage of a high-strength steel material, which is widely used in nuclear power industry, with the application of Small Punch Test method. Firstly, we prepared the small disk specimens in accordance with Small Punch Test method. Then we applied the technique of electrolytic hydrogen charging to the small disk specimens with different current strength. We executed macroscopic experiments on the hydrogen-charged specimens. The fracture surfaces of failed specimens were analyzed by the method of morphology observation and fracture analysis using scanning electron microscopy. It was found that the morphology of the fracture surfaces turned from ductile characteristics to brittle characteristics while the current intensity increased, namely the material brittleness was enhanced. Using theoretical analysis method, the conclusion that the concentration of hydrogen in the sample increases while the current density raises was obtained. Considering the conclusions by both of the experimental and theoretical analysis, we know that internal hydrogen degrades iron-based materials' mechanical properties. The brittleness of iron-based materials increases while the concentration of internal hydrogen increases. The research above allowed us to understand the phenomenon of hydrogen embrittlement much better.In order to have a further understanding of the mechanism of hydrogen embrittlement, we need to study the problem on micro scale. We chose the molecular dynamics method to study the influence of hydrogen-induced damage on BCC iron. We obtained the potential file by fitting the data of a well-used EAM potential model. We studied the mechanism of hydrogen embrittlement of single crystal BCC iron, as well as a series of coincidence site lattice types of grain boundaries by calculating their grain boundary energies. Then we selected several grain boundaries of interest as the objects to study the mechanism of hydrogen embrittlement of bi-crystal BCC iron. Based on the results of atomic-scale simulations, we discussed the mechanism of hydrogen-induced damage on BCC iron. For both single crystal and bi-crystal BCC iron, the main driving mechanism of hydrogen-induced damage is a combined action of hydrogen-enhanced decohesion theory, which is also known as the brittle lattice theory, and hydrogen-enhanced localized plasticity theory.