A nanoscale mechanism of hydrogen embrittlement in metals

Song, Jun; Curtin, W.A.

doi:10.1016/j.actamat.2010.11.019

Cited by 225 publications

(123 citation statements)

References 71 publications

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“…6 This concept and related models, [7][8][9] however, have not been made sufficiently predictive due to a lack of fundamental understanding of the chemomechanical mechanisms of embrittlement, despite considerable research effort. [10][11][12][13][14][15][16][17][18][19][20][21][22] One challenge towards such an understanding is to establish the mechanistic connections between the mechanochemistry of hydrogen adsorption and the strength reduction of grain boundaries (GBs) with realistic atomic structure and under loading conditions pertinent to applications.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen embrittlement of grain boundaries in nickel: an atomistic study

et al. 2017

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The chemomechanical degradation of metals by hydrogen is widely observed, but not clearly understood at the atomic scale. Here we report an atomistic study of hydrogen embrittlement of grain boundaries in nickel. All the possible interstitial hydrogen sites at a given grain boundary are identified by a powerful geometrical approach of division of grain boundary via polyhedral packing units of atoms. Hydrogen segregation energies are calculated at these interstitial sites to feed into the Rice-Wang thermodynamic theory of interfacial embrittlement. The hydrogen embrittlement effects are quantitatively evaluated in terms of the reduction of work of separation for hydrogen-segregated grain boundaries. We study both the fast and slow separation limits corresponding to grain boundary fracture at fixed hydrogen concentration and fixed hydrogen chemical potential, respectively. We further analyze the influences of local electron densities on hydrogen adsorption energies, thereby gaining insights into the physical limits of hydrogen embrittlement of grain boundaries.

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Section: Introductionmentioning

confidence: 99%

Hydrogen embrittlement of grain boundaries in nickel: an atomistic study

et al. 2017

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“…That is, is it a pre-requisite for hydrogen embrittlement or does it occur in association with the plasticity prior to or in association with crack nucleation and propagation? The hydrogen-triggered ductile-tobrittle transition mechanism, developed by Curtin and coworkers, is based on a finite-temperature coupled atomistic/discrete dislocation multi-scale method and large-scale molecular dynamics simulations of hydrogen processes at crack tips in Ni [35] and Fe. [36] They reported the accumulation of a high concentration of hydrogen at the crack tip, which in the Ni case they compared to a nano-hydride.…”

Section: Proposed Mechanismsmentioning

confidence: 99%

Hydrogen Embrittlement Understood

Robertson

Sofronis

Nagao

et al. 2015

Metall Mater Trans A

462

169

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The connection between hydrogen-enhanced plasticity and the hydrogen-induced fracture mechanism and pathway is established through examination of the evolved microstructural state immediately beneath fracture surfaces including voids, ''quasi-cleavage,'' and intergranular surfaces. This leads to a new understanding of hydrogen embrittlement in which hydrogenenhanced plasticity processes accelerate the evolution of the microstructure, which establishes not only local high concentrations of hydrogen but also a local stress state. Together, these factors establish the fracture mechanism and pathway.

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“…1) These failures have been generally attributed to the hydrogen-induced damages implying absorption, diffusion, trapping, and interactions of hydrogen atoms in steels. 2,3) Furthermore, complex microstructures due to severe deformation, 4,5) microalloying 6) and local welding 7) imply significant hydrogen trapping sources and also can contain bulk hydrogen concentrations higher than 10 wppm. An amount of the hydrogen penetration is measured by a hot extraction method; by heating a testing sample rapidly, hydrogen atoms located in lattices and trapped in defects are activated and diffuse out from the metallic sample.…”

Section: Introductionmentioning

confidence: 99%

Development of High Concentration References for Measuring Hydrogen Ingress into Steels

et al. 2014

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Hydrogen ingressed into steels has been treated as one of detrimental factors causing the hydrogeninduced damages or failures and its concentrations is generally measured by a hot extraction system calibrated with references. High concentration references above 50.00 wppm is proposed to solve the bottlenecks of conventional references such as thermal instability and lower hydrogen concentrations at room temperature; by varying a mixing amount of titanium hydride as a hydrogen source with its balancing iron bead, the synthesized reference has freely controlable hydrogen concentration and also showed a good thermal stability at room temperature. Hydrogen residue in the iron bead was controlled less than 0.13 wppm by an optimized procedure including wet cleaning and thermal soaking at 300°C for 3 minute. Hydrogen weight fraction in the titanium hydride was calculated by 0.04 based on the assumption of the stoichiometric composition (or TiH2). Hot extraction measurements and theoretical calculations of the hydrogen concentrations were done for the hydride-containing iron beads. Both data showed a good linear correlation each other and a validity of the proposed concept is confirmed emprically.

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A nanoscale mechanism of hydrogen embrittlement in metals

Cited by 225 publications

References 71 publications

Hydrogen embrittlement of grain boundaries in nickel: an atomistic study

Hydrogen embrittlement of grain boundaries in nickel: an atomistic study

Hydrogen Embrittlement Understood

Development of High Concentration References for Measuring Hydrogen Ingress into Steels

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