Electrochemical methods for studying diffusion, permeation and solubility of hydrogen in metals

Boes, N.; Züchner, H.

doi:10.1016/0022-5088(76)90037-0

Cited by 286 publications

(109 citation statements)

References 14 publications

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“…It will be interesting to examine the peculiarity of area and its influence on delayed fracture, for instance, heavy industrial region where air pollution level is high or coastal area in tropical region. 58,71) Electrochemical hydrogen permeation is an useful method to investigate hydrogen entry and diffusion in metals, [72][73][74][75][76][77][78][79][80][81] hydrogen traps, 81,82) and the method has been used to monitor hydrogen entry under outdoor exposure 34,38,83) and CCT 84) conditions. Omura et al have reported the correspondence between hydrogen permeation current at an exposure site and fracture ratio of exposure bolts.…”

Section: Ssrt After Outdoor Exposurementioning

confidence: 99%

Evaluation of Delayed Fracture Property of High Strength Bolt Steels

Akiyama

2012

ISIJ Int.

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Experimental studies attempting to evaluate the delayed fracture property of high strength bolt steels by using slow strain rate tests (SSRT) of circumferentially notched round bar specimens are reviewed in this paper. The relationship between the notch tensile strength (NTS) of the hydrogen-precharged specimens and the hydrogen content was approximated by power law relationship. It has been found that the local stress and the local diffusible hydrogen concentration control the occurrence of delayed fracture. To take into account the effect of hydrogen uptake from the environment, the notched bar specimens were subjected to cyclic corrosion test (CCT) and outdoor exposure, and their NTSs were measured using SSRT. The susceptibility of high strength steels to delayed fracture estimated from the decrease of NTS was correspondent to the fracture ratio of high strength bolts of the steels obtained by outdoor exposure tests, and was successfully evaluated with consideration of hydrogen uptake. Hydrogen entry behavior under CCT was monitored by electrochemical hydrogen permeation test, and continuous increase in hydrogen entry with growth of rust layer was observed. It is suggested that the "delay" of delayed fracture is the time required for the enhancement of the hydrogen entry efficiency.KEY WORDS: delayed fracture; hydrogen embrittlement; high strength steel; slow strain rate test; atmospheric corrosion; electrochemical hydrogen permeation; cyclic corrosion test; exposure test.

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Section: Ssrt After Outdoor Exposurementioning

confidence: 99%

Evaluation of Delayed Fracture Property of High Strength Bolt Steels

Akiyama

2012

ISIJ Int.

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“…A temperatura foi mantida constante a 25°C. A partir das curvas experimentais de permeação foi calculado o coeficiente de difusão aparente de hidrogênio (Dapp) usando o método do tempo tangente (breakthrough time) [14]. ) e foi selecionada com o intuito de permitir a interação entre o material e o hidrogênio preso durante a deformação causada pelo ensaio de CTOD.…”

Section: Materiais E Métodosunclassified

Estudo Da Difusão E Fragilização Por Hidrogênio Em Aço Inoxidável Superduplex

Ceballos¹,

Lage²,

Assis³

et al. 2017

Anais Do Congresso Anual Da ABM

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ResumoOs aços inoxidáveis duplex e superduplex são caracterizados por uma estrutura bifásica contendo ilhas de austenita precipitadas numa matriz de ferrita. Estes aços possuem boas propriedades mecânicas e boa resistência à corrosão. No entanto, estes aços podem apresentar fragilização por hidrogênio. No desenvolvimento deste trabalho se estudou a difusão e fragilização por hidrogênio de um aço inoxidável superduplex SAF 2507 nos estados como recebido e tratado térmicamente. Para avaliar a influência da microestrutura sobre a difusão do hidrogênio foram realizados ensaios de permeação electroquímica de hidrogênio. Observou-se que o coeficiente de difusão aparente aumenta em função da temperatura de recozimento. A influência de hidrogênio na resistência à fratura do material recozido a 1300°C foi estudada a partir de ensaios de tenacidade à fratura (CTOD). Determinou-se que a resistência à fratura do material diminui consideravelmente quando o mesmo é submetido a uma carga de hidrogênio. A presença de hidrogênio também modificou o mecanismo de fratura do material, observou-se uma fratura completamente dúctil no material que foi testado em ausência de hidrogênio e uma fratura frágil, caracterizada por clivagem, foi observada no material hidrogenado. Determinou-se que a fase austenítica pode ser fragilizada sob certas condições de carga de hidrogênio. Palavras-chave: Aços superduplex; Difusão de hidrogênio; Fragilização por hidrogênio; CTOD. STUDY OF HYDROGEN DIFUSSION AND EMBRITTLEMENT IN SUPER DUPLEX STAINLESS STEEL AbstractDuplex stainless steels are characterized by a biphasic structure containing austenite islands precipitated in the ferrite matrix. These steels have good mechanical properties and good corrosion resistance. However, these materials are susceptible to hydrogen embrittlement. In this work has been studied the hydrogen diffusion and embrittlement of super duplex stainless steel SAF 2507 in the material as received and annealed. To evaluate the influence of microstructure on the diffusion have been performed hydrogen electrochemical permeation tests. It was observed that the apparent diffusion coefficient increases with annealing temperature. The influence of hydrogen on toughness of the annealed material was studied using CTOD testing. It was determined that the fracture toughness of the material decreases considerably when it is subjected to hydrogen charge. The presence of hydrogen also changed the material fracture mechanism, a completely ductile fracture of the material has been observed in the material tested in the absence of hydrogen and a brittle fracture, characterized by cleavage, was observed in the hydrogenated material. It has been determined that the austenitic phase could be embrittle by hydrogen under certain conditions.

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“…The computational time step is set to ∆t = 5.0 × 10 −6 s and 1.0 × 10 −6 s in Case I and II, respectively. In both cases, the simulations are terminated at t max = 1.0 s. In order to compare with the experimental measurements, the hydrogen atomic fractions at film surface are converted into electric current using the relation (Boes and Züchner, 1976) 32) where I(t) denotes electric current at film surface, N A denotes the Avogadro constant, F denotes the Faraday constant, S = 1.2 cm 2 is surface area, and h (111) = ( √ 3/3)a H is the lattice spacing of (111) planes. A comparison of I(t) predicted by the simulations and the corresponding experimental data is shown in Fig.…”

Section: Model Validation For Hydrogen Desorption In Pd(111) Thin Filmsmentioning

confidence: 99%

Atomistic long-term simulation of heat and mass transport

Venturini

Wang

Romero

et al. 2014

Journal of the Mechanics and Physics of Solids

114

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We formulate a theory of non-equilibrium statistical thermodynamics for ensembles of atoms or molecules. The theory is an application of Jayne's maximum entropy principle, which allows the statistical treatment of systems away from equilibrium. In particular, neither temperature nor atomic fractions are required to be uniform but instead are allowed to take different values from particle to particle. In addition, following the Coleman-Noll method of continuum thermodynamics we derive a dissipation inequality expressed in terms of discrete thermodynamic fluxes and forces. This discrete dissipation inequality effectively sets the structure for discrete kinetic potentials that couple the microscopic field rates to the corresponding driving forces, thus resulting in a closed set of equations governing the evolution of the system. We complement the general theory with a variational meanfield theory that provides a basis for the formulation of computationally tractable approximations. We present several validation cases, concerned with equilibrium properties of alloys, heat conduction in silicon nanowires and hydrogen desorption from palladium thin films, that demonstrate the range and scope of the method and assess its fidelity and predictiveness. These validation cases are characterized by the need or desirability to account for atomiclevel properties while simultaneously entailing time scales much longer than * Corresponding author E-mail address: ortiz@caltech.edu (M. Ortiz). September 27, 2014 those accessible to direct molecular dynamics. The ability of simple meanfield models and discrete kinetic laws to reproduce equilibrium properties and long-term behavior of complex systems is remarkable. Preprint submitted to Journal of the Mechanics and Physics of Solids

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Electrochemical methods for studying diffusion, permeation and solubility of hydrogen in metals

Cited by 286 publications

References 14 publications

Evaluation of Delayed Fracture Property of High Strength Bolt Steels

Evaluation of Delayed Fracture Property of High Strength Bolt Steels

Estudo Da Difusão E Fragilização Por Hidrogênio Em Aço Inoxidável Superduplex

Atomistic long-term simulation of heat and mass transport

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