【摘要】 氢作为新型载能体在未来能源市场占据举足轻重的地位,然而金属材料的氢脆现象却成为阻碍氢能发展的主要瓶颈。由于原子氢在材料内部的固有本质(如可快速扩散、跨尺度分布以及不稳定性等),氢脆问题一直是个悬而未决但又引人入胜的科学问题。近20年来,随着多尺度力学表征技术的发展,冶金学者针对氢脆问题做了大量研究工作。本文基于此,综述了氢脆研究的最新进展:首先简述了表征材料氢脆倾向性的宏观力学尺度实验(如恒载荷、慢应变速率拉伸实验等)并对比分析各自优缺点;其次从介观尺度上分析了氢-压痕法的特点及主要应用范围;最后基于纳米压痕技术、微圆柱压缩和微悬臂梁弯曲以及环境TEM等原位力学实验表征材料在氢条件下的力学响应行为,重点讨论微纳观力学尺度上氢脆本质的最新研究成果;并对比分析不同实验结果,阐明其诠释氢脆机理的对立统一关系。更多还原

【Abstract】 Hydrogen is widely considered to be one of the future clean energy sources. A large scale of production, storage, transportation, and the use of hydrogen-related energy is likely to be escalated in the next few decades. However, the presence of hydrogen seriously deteriorates the mechanical properties of most structural metals, which is a main threat to the hydrogen economy. Although hydrogen embrittlement has been recognized for more than a century, there is still a lack of effective measures to eliminate this embrittlement in the engineering practices and some aspects of fundamental science; the embrittlement mechanism is still poorly understood. Because hydrogen is the lightest element in the universe, it exhibits several unique characteristics like permeability, fast diffusion, and unstable distribution in different scale defects. These characteristics are seriously affected by external stress, temperature, and other environmental factors. Therefore, the drawback of hydrogen embrittlement is still an extremely complex and attractive scientific topic. In the last two decades, with the development of multi-scale mechanical experimental techniques, various new studies on hydrogen embrittlement have been reported and its mechanism is deeply evaluated. Based on these advances, this review reflects on the complexity and importance of this topic. The macro-mechanical tests such as constant load and slow strain rate tensile tests are presented and their advantage and disadvantage on screening the susceptibility of materials to hydrogen embrittlement are compared. Subsequently, the hydrogen-indentation(hardness) method is introduced at the mesoscale to show the hydrogen-induced cracking and its application. Furthermore, the main focus of this review comprises the modern experimental approaches to fine-scale evaluation of the hydrogen-dislocation interaction, with particular emphasis on the nanoindentation pop-in effect, micro-pillar compression and micro-cantilever bending tests, and environmental transmission electron microscope tests. The fundamental principles of these approaches are overviewed, and their contribution to the elucidation of the hydrogen embrittlement mechanism is discussed. For example, the different effects of hydrogen on the mechanical properties and a mechanism similar to the hydrogen effect are proposed based on the micro-pillar compression and micro-cantilever bending tests. Nevertheless, there are still several discrepancies in the hydrogen-dislocation interaction that needs further investigation.更多还原