Cycled hydrogen permeation through Armco iron – A joint experimental and modeling approach

Drexler, Andreas; Siegl, Wolfgang; Ecker, Werner; Tkadletz, Michael; Klösch, Gerald; Schnideritsch, Holger; Mori, Gregor; Svoboda, Jiřı́; Fischer, F.D.

doi:10.1016/j.corsci.2020.109017

Cited by 27 publications

(26 citation statements)

References 37 publications

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“…4a. For the given charging conditions, the measured hydrogen contents increase linearly with increasing martensite area fraction, which could be due to hydrogen trapping at dislocations [38,41] in martensite, the lath martensite boundaries [20,42,43] or at ferrite/martensite interfaces [59,60]. This is in accordance with the experimental observations of Rudomilova et al [61], who estimated trap densities and effective diffusion coefficients of AHSS steel sheets as a function of the interface area between ferrite and martensite.…”

Section: Materials Characterizationsupporting

confidence: 85%

“…Trapped hydrogen can be regarded as reversibly trapped, whenever hydrogen absorption and/or desorption occur without significant microstructural changes at the sample surface. Typical reversible hydrogen trapping sites are directly accessible from the lattice sites, such as vacancies [25,36,38,39], dislocations [25,38,40], grain boundaries [36,38,41] or carbide interfaces [42][43][44][45][46]. According to McNabb and Foster [47], lattice hydrogen diffuses freely through the crystal structure, but trapped hydrogen exchanges only locally with lattice hydrogen.…”

Section: Bulk Diffusion Modellingmentioning

confidence: 99%

“…Fitting the predictions of the bulk diffusion model to the measured TDS spectrum enables determining the binding energy, the trap density and the migration energy [20,25,38,42,43]. For that purpose, the bulk diffusion as given in Eq.…”

Section: Bulk Diffusion Modellingmentioning

confidence: 99%

“…During this time, hydrogen was allowed to desorb from the surface at room temperature, causing a cosinusoidal profile of hydrogen concentration before temperature ramping. The routine for parameter optimization was developed in former works by the authors, and it uses the least square minimization method available in Python [38,42,43].…”

Section: Bulk Diffusion Modellingmentioning

confidence: 99%

“…The estimation according to the Kirchheim criterium gave binding energies between 18.3 and 30.7 kJ/mol. Hence, compared to micro-alloyed AHSS [42,43] DP steels contain mainly shallow hydrogen trapping sites, e.g., trapping sites at dislocations [36,38], lath martensite boundaries [42,43] or in volumes under micro-residual stress [53]. Although the titanium and niobium content in the chemical compositions of the investigated DP steels were not low, deep trapping sites, as they were found in literature for Titanium carbides and Niobium carbides [44,46,64], could not be observed in the measured TDS spectra.…”

Section: Characterization Of Hydrogen Content and Desorption Energymentioning

confidence: 99%

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The role of hydrogen diffusion, trapping and desorption in dual phase steels

et al. 2022

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Hydrogen embrittlement (HE) of advanced high-strength steels is a crucial problem in the automotive industry, which may cause time-delayed failure of car body components. Practical approaches for evaluating the HE risk are often partially and contradictive in nature, because of hydrogen desorption during testing and inhomogenous hydrogen distributions in, e.g., notched samples. Therefore, the present work aims to provide fully parametrized and validated bulk diffusion models for three dual phase steels to simulate long-range chemical diffusion, trapping and hydrogen desorption from the surface. With one constant set of parameters, the models are able to predict the temperature dependency of measured Choo-Lee plots as well as the concentration dependency of measured effective diffusion coefficients. Finally, the parametrized and validated bulk diffusion models are applied for studying the role of the current density on the permeation time and the role of coatings as effective diffusion barriers. Graphical abstract

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Section: Materials Characterizationsupporting

confidence: 85%

Section: Bulk Diffusion Modellingmentioning

confidence: 99%

Section: Bulk Diffusion Modellingmentioning

confidence: 99%

Section: Bulk Diffusion Modellingmentioning

confidence: 99%

Section: Characterization Of Hydrogen Content and Desorption Energymentioning

confidence: 99%

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The role of hydrogen diffusion, trapping and desorption in dual phase steels

et al. 2022

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Effect of Tensile Loading and Temperature on the Hydrogen Solubility of Steels at High Gas Pressure

Drexler,

Konert,

Nietzke

et al. 2023

steel research int.

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The hydrogen solubility in ferritic and martensitic steels is affected by hydrostatic stress, pressure and temperature. In general, compressive stresses decrease but tensile stresses increase the hydrogen solubility. This important aspect must be considered when qualifying materials for high‐pressure hydrogen applications (e.g., for pipelines or tanks) by using autoclave systems. This work proposes a pressure equivalent for compensating the effect of compressive stresses on the hydrogen solubility inside of closed autoclaves, to achieve solubilities that are equivalent to those in pipelines and tanks subjected to tensile stresses. Moreover, it is shown that the temperature effect becomes critical at low temperatures (e.g., under cryogenic conditions for storing liquid hydrogen). Trapping of hydrogen in the microstructure can increase the hydrogen solubility with decreasing temperature, having a solubility minimum at about room temperature. In order to demonstrate this effect, the generalized law of the hydrogen solubility is parametrized for different steels using measured contents of gaseous hydrogen. The constant parameter sets are verified and critically discussed with respect to the high‐pressure hydrogen experiments.This article is protected by copyright. All rights reserved.

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