L'hydrogène dans les matériaux métalliques en relation avec les interactions plasticité-environnement

Abstract

Résumé. L'objectif de cet article est de faire une revue synthétique des données de la littérature qui permettent de caractériser le comportement de l'hydrogène dans les matériaux métalliques et plus particulièrement les effets d'endommagement associés à l'hydrogène en relation avec les interactions plasticité-environnement. Dans cette présentation générale nous nous sommes limités au comportement de l'hydrogène dans les matériaux de structure tels que les alliages base fer et base nickel.Les principaux points abordés dans cette présentation sont : -des généralités sur l'absorption de l'hydrogène dans ces alliages : diffusion, perméation, piégeage, -une courte revue des principaux effets d'endommagement associés à l'absorption d'hydrogène, -quelques remarques spécifiques aux interactions hydrogène-plasticité.

Communication—The Mechanism of Hydrogen Permeation Resistance of Ni Coating Enhanced by the Incorporation of Graphene

“…Recently, more and more attention has been paid to Ni coating as a promising barrier against hydrogen diffusion towards steels since the diffusion coefficient of hydrogen in Ni was lower by 3 ∼ 4 orders magnitudes than that in common commercial steels. 1,2 Gaspard and D. Delafosse 3 used the electrodeposited Ni layer to control the desorption rate of hydrogen in steel sample after hydrogenation. It was also reported in some studies that Ni coating could provide the protective effect at some extent against hydrogen embrittlement (HE) in steels since it could hinder the uptake of hydrogen towards steels.…”

Graphene Containing Composite Coatings as a Protective Coatings against Hydrogen Embrittlement in Quenching & Partitioning High Strength Steel

“…It is hard to reach a consensus on the effect of Ni coatings on HE. 13,[18][19][20][21][22] Chêne 21 suggested that the diffusion coefficient of hydrogen in Nickel was 5.3 × 10 −10 cm 2 •s −1 , which is much lower than that of common steel (10 −5 ∼10 −8 cm 2 •s −1 ). Ni electrodeposited layer controlling hydrogen desorption rate was successfully prepared on the surface of ferrite steel by Gaspard et al 22 However, Michler et al 20 found that Ni coatings did not significantly improve the tensile ductility (elongation or reduction of area) in hydrogen atmosphere compared the untreated specimens, for which the main reason was ascribed to the defects of coatings and the bad adhesion on substrate.…”

Modelling of the effect of dislocation channel on intergranular microcrack nucleation in pre-irradiated austenitic stainless steels during low strain rate tensile loading

“…This expression is plotted versus hydrogen concentration (Fig. 12) considering PWR water temperature (573 K) and DH b = 20 kJ/mol [51]. It can be observed that for a hydrogen concentration comprises between 500 and 3000 appm, the equilibrium occupancy fraction of hydrogen is comprised between 0.003 and 0.02.…”