Röhsler Andreas, Sobol Oded, Hänninen Hannu, Böllinghaus Thomas
Federal Institute for Materials Research and Testing, Department for Component Safety, Berlin, 12205, Germany.
Aalto University, Department of Mechanical Engineering, Espoo, 00076, Finland.
Sci Rep. 2020 Feb 27;10(1):3611. doi: 10.1038/s41598-020-60370-2.
Hydrocarbons fuel our economy. Furthermore, intermediate goods and consumer products are often hydrocarbon-based. Beside all the progress they made possible, hydrogen-containing substances can have severe detrimental effects on materials exposed to them. Hydrogen-assisted failure of iron alloys has been recognised more than a century ago. The present study aims to providing further insight into the degradation of the austenitic stainless steel AISI 304L (EN 1.4307) exposed to hydrogen. To this end, samples were electrochemically charged with the hydrogen isotope deuterium (H, D) and analysed by scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). It was found that deuterium caused a phase transformation from the original γ austenite into ε- and α'-martensite. Despite their low solubility for hydrogen, viz. deuterium, the newly formed phases showed high deuterium concentration which was attributed to the increased density of traps. Information about the behaviour of deuterium in the material subjected to external mechanical load was gathered. A four-point-bending device was developed for this purpose. This allowed to analyse in-situ pre-charged samples in the ToF-SIMS during the application of external mechanical load. The results indicate a movement of deuterium towards the regions of highest stress.
碳氢化合物为我们的经济提供动力。此外，中间产品和消费品通常是以碳氢化合物为基础的。尽管含氢物质带来了诸多进步，但它们可能会对接触到的材料产生严重的不利影响。铁合金的氢致失效早在一个多世纪前就已被认识到。本研究旨在进一步深入了解奥氏体不锈钢AISI 304L（EN 1.4307）在接触氢时的降解情况。为此，对样品进行了氢同位素氘（H，D）的电化学充电，并通过扫描电子显微镜（SEM）、电子背散射衍射（EBSD）和飞行时间二次离子质谱（ToF-SIMS）进行分析。结果发现，氘导致了从原始γ奥氏体向ε - 和α' - 马氏体的相变。尽管新形成的相对氢（即氘）的溶解度较低，但它们显示出高氘浓度，这归因于陷阱密度的增加。收集了有关氘在承受外部机械载荷的材料中的行为信息。为此开发了一种四点弯曲装置。这使得在施加外部机械载荷期间能够在ToF-SIMS中对预先充电的样品进行原位分析。结果表明氘向应力最高的区域移动。
