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Hydrogen-enhanced grain boundary vacancy stockpiling causes transgranular to intergranular fracture transition

Ding, Yu and Yu, Haiyang and Lin, Meichao and Zhao, Kai and Xiao, Senbo and Vinogradov, Alexei and Qiao, Lijie and Ortiz, Michael and He, Jianying and Zhang, Zhiliang (2022) Hydrogen-enhanced grain boundary vacancy stockpiling causes transgranular to intergranular fracture transition. Acta Materialia, 239 . Art. No. 118279. ISSN 1359-6454. doi:10.1016/j.actamat.2022.118279.

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The attention to hydrogen embrittlement (HE) has been intensified recently in the light of hydrogen as a carbon-free energy carrier. Despite worldwide research, the multifaceted HE mechanism remains a matter of debate. Here we report an atomistic study of the coupled effect of hydrogen and deformation temperature on the pathway to intergranular fracture of nickel. Uniaxial straining is applied to nickel Σ5(210)[001] and Σ9(1-10)[22-1] grain boundaries with or without pre-charged hydrogen at various temperatures. Without hydrogen, vacancy generation at grain boundary is limited and transgranular fracture mode dominates. When charged, hydrogen as a booster can enhance strain-induced vacancy generation by up to ten times. This leads to the superabundant vacancy stockpiling at the grain boundary, which agglomerates and nucleates intergranular nanovoids eventually causing intergranular fracture. While hydrogen tends to persistently enhance vacancy concentration, temperature plays an intriguing dual role as either an enhancer or an inhibitor for vacancy stockpiling. These results show good agreement with recent positron annihilation spectroscopy experiments. An S-shaped quantitative correlation between the proportion of intergranular fracture and vacancy concentration was for the first time derived, highlighting the existence of a critical vacancy concentration, beyond which fracture mode will be completely intergranular.

Item Type:Article
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URLURL TypeDescription
Yu, Haiyang0000-0002-2419-6736
Zhao, Kai0000-0003-2645-7917
Vinogradov, Alexei0000-0001-9585-2801
Ortiz, Michael0000-0001-5877-4824
Additional Information:© 2022 The Author(s). Published by Elsevier Ltd on behalf of Acta Materialia Inc. Under a Creative Commons license - Attribution 4.0 International (CC BY 4.0). Received 24 April 2022, Revised 8 August 2022, Accepted 15 August 2022, Available online 17 August 2022. Y.D. acknowledge the financial support provided by the Research Council of Norway under the M-HEAT project (Grant No. 294689) and the HyLINE project (Grant No. 294739). All simulations are carried out on the Fram (Grant No. NN9110K, NN9391K) high-performance computer clusters at NTNU, Trondheim. Author contribution. The project was planned and supervised by Z.Z., J.H., H.Y. The simulation design and data analysis were performed by Y.D. All authors participated in the discussion and co-wrote the paper. Data availability. The data that support the findings of this study are available from the corresponding authors upon request. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Funding AgencyGrant Number
Research Council of Norway294689
Research Council of Norway294739
Norwegian Metacenter for Computational ScienceNN9110K
Norwegian Metacenter for Computational ScienceNN9391K
Subject Keywords:Hydrogen embrittlement; Intergranular failure; Vacancies; Grain boundaries; Molecular dynamics (MD)
Record Number:CaltechAUTHORS:20220817-896609000
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Official Citation:Yu Ding, Haiyang Yu, Meichao Lin, Kai Zhao, Senbo Xiao, Alexei Vinogradov, Lijie Qiao, Michael Ortiz, Jianying He, Zhiliang Zhang, Hydrogen-enhanced grain boundary vacancy stockpiling causes transgranular to intergranular fracture transition, Acta Materialia, 2022, 118279, ISSN 1359-6454,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:116348
Deposited By: George Porter
Deposited On:18 Aug 2022 20:15
Last Modified:12 Oct 2022 22:58

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