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

Ding, YuNorwegian Univ Sci & Technol NTNU, Dept Struct Engn, N-7491 Trondheim, Norway. (författare)

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 mat-ter 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 E5(210)[001] and E9(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 frac-ture mode dominates. When charged, hydrogen as a booster can enhance strain-induced vacancy genera-tion 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 hy-drogen 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, highlight-ing the existence of a critical vacancy concentration, beyond which fracture mode will be completely intergranular.

Yu, Haiyang,PhD,1989-Uppsala universitet,Tillämpad mekanik(Swepub:uu)haiyu615 (författare)
Lin, MeichaoNorwegian Univ Sci & Technol NTNU, Dept Struct Engn, N-7491 Trondheim, Norway. (författare)
Zhao, KaiJiangnan Univ, Jiangsu Key Lab Adv Food Mfg Equipment & Technol, Wuxi 214122, Peoples R China. (författare)
Xiao, SenboNorwegian Univ Sci & Technol NTNU, Dept Struct Engn, N-7491 Trondheim, Norway. (författare)
Vinogradov, AlexeyNorwegian Univ Sci & Technol NTNU, Dept Mech & Ind Engn, N-7491 Trondheim, Norway. (författare)
Qiao, LijieUniv Sci & Technol Beijing, Beijing Adv Innovat Ctr Mat Genome Engn, Beijing 100083, Peoples R China. (författare)
Ortiz, MichaelCALTECH, Grad Aerosp Labs, 1200 E Calif Blvd, Pasadena, CA 91125 USA. (författare)
He, JianyingNorwegian Univ Sci & Technol NTNU, Dept Struct Engn, N-7491 Trondheim, Norway. (författare)
Zhang, ZhiliangNorwegian Univ Sci & Technol NTNU, Dept Struct Engn, N-7491 Trondheim, Norway. (författare)
Norwegian Univ Sci & Technol NTNU, Dept Struct Engn, N-7491 Trondheim, Norway.Tillämpad mekanik (creator_code:org_t)

Av författaren/redakt...: Ding, Yu; Yu, Haiyang, PhD ...; Lin, Meichao; Zhao, Kai; Xiao, Senbo; Vinogradov, Alex ...; visa fler...; Qiao, Lijie; Ortiz, Michael; He, Jianying; Zhang, Zhiliang; visa färre...

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