文献类型：期刊文献

英文题名：Segregation at prior austenite grain boundaries: the competition between boron and hydrogen

作者：Hachet, Guillaume[1]; Tehranchi, Ali[1]; Shi, Hao[1]; Prabhakar, Manoj[1]; Wei, Shaolou[1]; Angenendt, Katja[1]; Zaefferer, Stefan[1]; Gault, Baptiste[1,3]; Sun, Binhan[1,2]; Ponge, Dirk[1]; Raabe, Dierk[1]

机构：[1] Department of Microstructure Physics and Alloys Design, Max-Planck-Institut für Nachhaltige Materialien, Düsseldorf, 40237, Germany; [2] Key Laboratory of Pressure Systems and Safety, Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, China; [3] Department of Materials, Royal School of Mines, Imperial College London, Prince Consort Road, London, SW7 2BP, United Kingdom

年份：2024

外文期刊名：arXiv

收录：EI(收录号：20244717403597)

语种：英文

外文关键词：Grain size and shape - Segregation (metallography) - Thermal desorption - Thermal desorption spectroscopy - Thermolysis

摘要：The interaction between boron and hydrogen at grain boundaries has been investigated experimentally and numerically in boron-doped and boron-free martensitic steels using thermal desorption spectrometry (TDS) and ab initio calculations. The calculations show that boron and hydrogen are attracted to grain boundaries but boron can repel hydrogen. This behavior has also been observed using TDS measurements, with the disappearance of one peak when boron is incorporated into the microstructure. Additionally, the microstructure of both steels has been studied through electron backscattered diffraction, synchrotron X-ray measurements, and correlative transmission Kikuchi diffraction-atom probe tomography measurements. While they have a similar grain size, grain boundary distribution, and dislocation densities, pronounced boron segregation into PAGBs is observed for boron-doped steels. It indicates that boron in PAGBs is responsible for the disappearance of the TDS peaks for the boron-doped steel. Then, the equilibrium hydrogen concentration in different trapping sites has been evaluated using the Langmuir-McLean approximation. This thermodynamic model shows that the distribution of hydrogen is identical for all traps when the total hydrogen concentration is low for boron-free steel. However, when it increases, traps of the lowest segregation energies (mostly PAGBs) are firstly saturated, which promotes failure initiation at this defect type. This finding partially explains why PAGBs are the weakest microstructure feature when martensitic steels are exposed to hydrogen-containing environments. ? 2024, CC BY.