Hydrogen-induced compatibility constraints across grain boundaries drive intergranular failure of Ni

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:760

Article

Bertsch, K. M.^1,2,3  Wang, S.^4,5  Nagao, A.^2,6  Robertson, I. M.^3,4 

[1] Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA

[2] Kyushu Univ, I2CNER, WPI, Nishi Ku, 744 Motooka, Fukuoka 8190395, Japan

[3] Univ Wisconsin, Dept Mat Sci & Engn, 1509 Univ Ave, Madison, WI 53706 USA

[4] Univ Wisconsin, Dept Engn Phys, Madison, WI 53706 USA

[5] Southern Univ Sci & Technol, Dept Mech & Energy Engn, 1088 Xueyuan Blvd, Shenzhen 518055, Peoples R China

[6] JFE Steel Corp, Steel Res Lab, Mat Surface & Interface Sci Res Dept, Kawasaki Ku, 1-1 Minamiwatarida Cho, Kawasaki, Kanagawa 2100855, Japan

关键词: Hydrogen embrittlement;    Multi-scale;    Grain boundaries;    Hydrogen-enhanced plasticity;   

DOI  :  10.1016/j.msea.2019.05.036

来源: Elsevier

【 摘 要 】

A multi-scale experimental approach was used to determine the fundamental mechanisms responsible for the hydrogen-induced transition in failure mode from ductile transgranular to intergranular in polycrystalline Ni during uniaxial loading. Hydrogen accelerated the evolution of the deformation microstructure, producing smaller dislocation cells and microbands, and causing significantly different orientation deviations to develop in neighboring grains, while inducing less evolution of texture, less grain rotations, less elongation of the grains parallel to the tensile axis, and greater out-of-surface distortion of the grains. These observations are explained in terms of the hydrogen-enhanced plasticity mechanism, which results in a redistribution of hydrogen that stabilizes the deformed microstructure and increases the hydrogen coverage on the grain boundaries. The stabilization of the microstructure manifests as a reduced ability of grains to cooperatively accommodate evolving deformation structures, which introduces an additional compatibility constraint across grain boundaries. The combination of this compatibility constraint across grain boundaries, the locking of the microstructure in a specific configuration by hydrogen, and the hydrogen-weakening of the grain boundaries drives the hydrogen-induced intergranular failure.

【 授权许可】

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