Effect of local chemistry on microstructural stability and local deformation mechanisms in relation to hydrogen embrittlement of Fe base fcc alloys

局部化学对铁基面心立方合金氢脆相关微观结构稳定性和局部变形机制的影响

• 批准号: 267495973
• 负责人: Professor Dr.-Ing. Werner Theisen, since 2/2017
• 金额: --
• 依托单位: Universidad Pedagógica y Tecnológica de Columbia
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/267495973?language=en
• 关键词: Effect; local; chemistry; microstructural; stability

Hydrogen embrittlement of technical Fe base alloys with face centered cubic crystal structure is a topic that has been intensively investigated for decades. The reason for that is the high technical relevance of this topic. It gains even more importance due to the recent discussion on renewable energy sources and the use of hydrogen for energy storage. Concerning embrittlement mechanisms of metals, mainly three theories are discussed in literature, namely the hydrogen induced decohesion, the formation of metal hydrides, and the HELP mechanism (hydrogen enhanced localized plasticity). For certain, usually standardized, alloys, the mechanisms of hydrogen embrittlement are known. However, for austenitic steels there is still a lack of information to relate the macroscopic properties in the presence of hydrogen with microstructural properties, the latter being a result of production and processing of these high-alloyed materials. Published works often makes use of well-known and standardized materials without considering the procedural and thermomechanical history. The objective of the research project is to make a contribution to fill this gap of knowledge. To do so, pre-defined model systems of iron based alloys shall be investigated with respect to solidification and distribution of alloying elements being a result of segregation. Simulations on the basis of the CALPHAD and the phase field method will be applied along with WDS- and EDS-measurements. Investigations of the local deformation and failure mechanisms with and without the presence of external hydrogen will be performed ex-situ by space-resolved diffraction methods (EBSD). The overall aim of the research project is the prediction of local chemical compositions and to derive local materials properties (e.g. phase stability, stacking fault energy) from that. Finally, this information shall be correlated with the local influence of hydrogen that controls the macroscopic properties of the material.

具有面心立方晶体结构的工业铁基合金的氢脆是几十年来研究的热点。其原因是这一主题的高度技术相关性。由于最近关于可再生能源和使用氢进行能量储存的讨论，它变得更加重要。关于金属的脆化机理，文献中主要讨论了三种理论，即氢致脱粘理论、金属微裂纹的形成理论和氢增强局部塑性（HELP）机制。对于某些通常标准化的合金，氢脆机理是已知的。然而，对于奥氏体钢，仍然缺乏将氢存在下的宏观性能与微观结构性能相关联的信息，后者是这些高合金材料的生产和加工的结果。出版的作品通常使用众所周知的标准化材料，而不考虑程序和热机械历史。该研究项目的目标是为填补这一知识空白做出贡献。为此，应研究铁基合金的预定义模型系统，以了解合金元素的凝固和分布，这是偏析的结果。将沿着使用基于CALPHAD和相场法的模拟以及WDS和EDS测量。将通过空间分辨衍射方法（EBSD）对有和没有外部氢存在的局部变形和失效机制进行非原位研究。该研究项目的总体目标是预测局部化学成分，并从中得出局部材料特性（例如相稳定性，堆垛层错能）。最后，该信息应与控制材料宏观特性的氢的局部影响相关。