Study of hydrogen embrittlement behavior by using pure Fe containing high-density lattice defects

晶粒细化对生产高强度金属很重要，因为细化可以提高强度和韧性。在过去的十年中，通过高压扭转(HPT)应变等严重塑性变形(SPD)制备块体纳米/亚微米结构金属的研究取得了进展。这种经SPD处理的金属通常表现出极高的强度和延展性。然而，钢的抗拉强度超过1.2 Gpa通常会导致氢脆(HE)。在本研究中，通过宽应变速率(10-3~10+3 S-1)拉伸试验研究了高强应变制备的纳米结构纯铁在拉伸试验过程中晶格缺陷与氢的相互作用。此外，我们还用断口分析了氢对空穴形成/裂纹扩展的影响与断裂/动态响应之间的关系。

Grain refinement is important to create high strength metals, since both strength and toughness can be improved by grain refining. During the past decade, fabrication of bulk nano- / submicron- structured metals by severe plastic deformation (SPD), such as high-pressure torsion (HPT) straining, has evolved. Such SPD-processed metals often show extraordinary high strength and ductility. However, increase in tensile strength over 1.2 GPa in steels generally lead to hydrogen embrittlement (HE).In this study, HE behavior was investigated by means of tensile test with wide-range strain rate of 10 -3 ~ 10 +3 s-1 in the nano-structured pure Fe produced by HPT-straining, since this investigation focused on the interaction of lattice defects and hydrogen in the sample during tensile test. In addition, we made the correlation between the influence of hydrogen on the void formation / crack propagation and the fracture / dynamic response by means of fractography.