Meso-scale anisotropic hydrogen segregation near grain-boundaries in polycrystalline nickel characterized by EBSD/SIMS

Journal Article · Mon Feb 15 04:00:00 EST 2016 · Materials Letters

DOI:https://doi.org/10.1016/j.matlet.2015.12.016· OSTI ID:1243201

Oudriss, A.; Le Guernic, Solenne; Wang, Zhaoying; Osman Hock, B.; Bouhattate, Jamaa; Conforto, E.; Zhu, Zihua; Li, Dongsheng; Feaugas, Xavier

To study anisotropic hydrogen segregation and diffusion in nickel polycrystalline, Secondary Ion Mass Spectrometry (SIMS) and Electron Back Scattered Diffraction (EBSD) are integrated to investigate hydrogen distribution around grain boundaries. Hydrogen distribution in pre-charged samples were correlated with grain boundary character by integrating high-resolution grain microstructure from EBSD inverse pole figure map and low-resolution hydrogen concentration profile map from SIMS. This multimodal imaging instrumentation shows that grain boundaries in nickel can be categorized into two families based on behavior of hydrogen distribution crossing grain boundary: the first one includes random grain boundaries with fast hydrogen diffusivity, showing a sharp gap for hydrogen concentration profile cross the grain boundaries. The second family are special Σ3n grain boundaries with low hydrogen diffusivity, showing a smooth gradient of hydrogen concentration cross the grain boundary. Heterogeneous hydrogen distributions due to grain boundary family revealed by SIMS/EBSD on mesoscale further validate the recent hydrogen permeation data and anisotropic ab-initio calculations in nanoscale. The results highlight the fact that grain boundaries character impacts hydrogen distribution significantly.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1243201
• Report Number(s): PNNL-SA-115815; 47721; KP1704020
• Journal Information: Materials Letters, Journal Name: Materials Letters Vol. 165; ISSN 0167-577X
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

Electron Back Scattered Diffraction
Environmental Molecular Sciences Laboratory
Secondary Ion Mass Spectrometry
hydrogen
nickel