Hydrogen trapping mechanisms by permeation techniques

Johnson, H. H.; Quick, Nathaniel R.; Kumnick, A. J.

doi:10.1016/0036-9748(79)90392-2

Cited by 66 publications

(11 citation statements)

References 10 publications

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“…Plastic deformation leads to a decrease of D eff (Table III), in agreement with the findings of previous studies on hydrogen permeation in cold-rolled iron [19,56] and in low-strength steels. [19,22,24,41] As shown by the data of Table III plotted in Figure 2, the deformation-induced decrease of D eff is moderate (factor of 2 at most), with regard to the large plastic deformation in the homogeneous deformation range given to the samples.…”

Section: Influence Of Plastic Deformationsupporting

confidence: 91%

Quantification of hydrogen diffusion and trapping in 2.25Cr-1Mo and 3Cr-1Mo-V steels with the electrochemical permeation technique and melt extractions

Brass

Guillon

Vivet

2004

Metall Mater Trans A

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The electrochemical permeation technique was used to investigate the effect of microstructure, hydrogen activity, and stationary dislocations generated by tensile straining on the permeation and degassing of hydrogen. A conventional 2.25Cr-1Mo steel, with which the existing hydrotreating reactors are made, and a 3Cr-1Mo-V steel, which is a candidate material for the future generation of reactors, were selected for this study. The effective diffusion coefficient of hydrogen derived from permeation and degassing transients shows a slower diffusivity in the V-containing steel at room temperature, regardless of the hydrogen activity. A large plastic deformation obtained by tensile straining in the homogeneous deformation domain only leads to a moderate decrease of the hydrogen diffusivity in both steels. The results are compared with the literature data on hydrogen permeation in iron and ferritic steels. On the other hand, the hydrogen content was measured with the melt extraction method after cathodic charging and subsequent aging at room temperature for different times to determine the diffusible (lattice ϩ reversibly trapped) hydrogen concentration. It was shown that the latter is larger in 3Cr-1Mo-V steel, which contains, in addition, a large fraction of "strong reversible" traps. A good concordance was found between the diffusible hydrogen concentration values computed from steady-state permeation measurements and from graphical integration of decay transients. The validity of the quantification, from permeation experiments, of the diffusible hydrogen concentration in materials with complex microstructures is discussed.

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Section: Influence Of Plastic Deformationsupporting

confidence: 91%

Quantification of hydrogen diffusion and trapping in 2.25Cr-1Mo and 3Cr-1Mo-V steels with the electrochemical permeation technique and melt extractions

Brass

Guillon

Vivet

2004

Metall Mater Trans A

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“…This result virtually coincides with the standard Oriani-theory equation of diffusion [8,26,34,50], which was initially posed [50] and used [8] as an implementation of Oriani's [13] local equilibrium hypothesis at small values of θ L . Here, this equation is Philosophical Magazine obtained as a particularisation of Equation (43), which was derived for arbitrary occupancies.…”

Section: Small Concentration Of Traps N τ << N L (γ T << 1)supporting

confidence: 67%

A generalised model of hydrogen diffusion in metals with multiple trap types

Toribio

Kharin

2015

Philosophical Magazine

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Continuum modelling of hydrogen diffusion in metals, which accounts for both trapping and an imposed force field, is revisited. A generalised model of hydrogen diffusion and trapping is developed as a continuous interpretation of the discrete random-walk theory. A system of nonlinear equations describing the phenomenon of diffusion with multiple types of traps is derived without the assumption of a local equilibrium among hydrogen populations in dissimilar positions. Lattice-trap interchange kinetics can degenerate into local equilibrium as a limit case. Moreover, certain terms in general equations may be negligible in specific situations. By removing these terms, known particularised models of hydrogen diffusion and trapping are recovered. Determining the terms, which are disregarded in reduced models, enables a straightforward assessment of the applicability of these models. The advantages and limitations of particularised models applied to hydrogen embrittlement analyses are discussed.

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“…To instance, a customary particularisation [5,7,10] of the equilibrium partitioning (3) was adopted in the commented papers [1e4] that can be phrased as follows:…”

Section: Objectionsmentioning

confidence: 99%

“…As the basement for valuation of the role of traps in hydrogen diffusion, they invoked the model, which keystone equation was posed by Johnson et al [5] as the implementation of Oriani's [6] hypothesis of local latticeetrap equilibrium. Since then, it has been employed in analyses and simulations for decades, see, e.g., [7e10].…”

mentioning

confidence: 99%

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Comments on “Computational analysis of geometrical factors affecting experimental data extracted from hydrogen permeation tests: I – Consequences of trapping” [Int J Hydrogen Energy 36 (2011) 12644–12652] and “… II – Consequences of trapping and an oxide layer” [Int J Hydrogen Energy 37 (2012) 13574–13582], “Corrigenda …” to both [Int J Hydrogen Energy 39 (2014) 2430], and on “… III – Comparison with experimental results from the literature” [Int J Hydrogen Energy 39 (2014) 1145–1155] with “Generalized mod

Kharin

2014

International Journal of Hydrogen Energy

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DiscussionComments on "Computational analysis of geometrical factors affecting experimental data extracted from hydrogen permeation tests: I e Consequences of trapping" [Int J Hydrogen Energy 36 (2011) 12644e12652] and "… II e Consequences of trapping and an oxide layer" [Int J Hydrogen Energy 37 (2012) 13574e13582], "Corrigenda …" to both [Int J Hydrogen Energy 39 (2014) 2430], and on "… III e Comparison with experimental results from the literature" [Int J Hydrogen Energy 39 (2014) 1145e1155] with "Generalized model of desorption kinetics: Characterization of hydrogen trapping in a homogeneous membrane" [Int J Hydrogen Energy 39 (2014) 8374e8384] a b s t r a c t Considering the quoted hydrogen permeation analyses that take into account the species trapping in the course of diffusion, these comments call into question the congruity between performed computations and the model of hydrogen diffusion and trapping in metals used there as the theoretical basement. Presented reasoning brings doubts that the equation of diffusion and trapping implemented in referred calculations matches with the adopted theoretical framework. Adduced derivations evidence their disagreement. In consequence, addressed numerical simulations and recommendations deduced therefrom deserve reconsideration.ScienceDirect j ou rnal h ome pag e: www.elsevier.com/loca te/he i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 3 9 ( 2 0 1 4 ) 1 9 8 4 6 e1 9 8 5 0 http://dx.

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Hydrogen trapping mechanisms by permeation techniques

Cited by 66 publications

References 10 publications

Quantification of hydrogen diffusion and trapping in 2.25Cr-1Mo and 3Cr-1Mo-V steels with the electrochemical permeation technique and melt extractions

Quantification of hydrogen diffusion and trapping in 2.25Cr-1Mo and 3Cr-1Mo-V steels with the electrochemical permeation technique and melt extractions

A generalised model of hydrogen diffusion in metals with multiple trap types

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