Hajilou T, Deng Y, Kheradmand N, Barnoush A
Department of Mechanical and Industrial Engineering, NTNU Richard Birkelands vei 2b, 7491, Trondheim, Norway.
Department of Mechanical and Industrial Engineering, NTNU Richard Birkelands vei 2b, 7491, Trondheim, Norway
Philos Trans A Math Phys Eng Sci. 2017 Jul 28;375(2098). doi: 10.1098/rsta.2016.0410.
Hydrogen (H) enhanced cracking was studied in Fe-3wt%Si by means of electrochemical microcantilever bending test. It was clearly shown that the presence of H causes hydrogen embrittlement (HE) by triggering crack initiation and propagation at the notch where stress concentration is existing. Additionally, the effect of carbon content and the presence of a grain boundary (GB) in the cantilever were studied. It was shown that in the presence of H the effect of carbon atom on pinning the dislocations is reduced. On the other hand, the presence of a GB, while the chemical composition of material kept constant, will promote the HE. Crack initiation and propagation occur in the presence of H, while the notch blunting was observed for both single and bi-crystalline beams bent in air. Post-mortem analysis of the crack propagation path showed that a transition from transgranular fracture to intragranular fracture mechanism is highly dependent on the position of the stress concentration relative to the GB.This article is part of the themed issue 'The challenges of hydrogen and metals'.
通过电化学微悬臂梁弯曲试验研究了铁硅（Fe-3wt%Si）中的氢（H）增强开裂现象。结果清楚地表明，氢的存在通过在存在应力集中的缺口处引发裂纹萌生和扩展，从而导致氢脆（HE）。此外，还研究了碳含量和悬臂梁中晶界（GB）的存在所产生的影响。结果表明，在氢存在的情况下，碳原子对位错的钉扎作用减弱。另一方面，在材料化学成分保持不变的情况下，晶界的存在会促进氢脆。在氢存在的情况下会发生裂纹萌生和扩展，而在空气中弯曲的单晶和双晶梁均观察到缺口钝化现象。对裂纹扩展路径的事后分析表明，从穿晶断裂到沿晶断裂机制的转变高度依赖于应力集中相对于晶界的位置。本文是主题为“氢与金属的挑战”的特刊的一部分。
