Hydrogen Embrittlement Research Articles

Research status of reversed austenite in martensite: Review

Abstract This paper studies the role of reversed austenite in martensitic stainless steels, summarizes the formation principles of reversed austenite in martensitic stainless steels and reviews elements influencing its formation. It also summarizes common heat treatment methods for obtaining reversed austenite in martensitic stainless steels and compares the advantages and disadvantages of various approaches. For example, layered quenching and tempering yield more reversed austenite compared to simple tempering, resulting in finer microstructures at room temperature.The paper analyzes how different reversed austenite contents affect the strength, ductility, and hardness of martensitic stainless steels, as well as the impact on pitting, intergranular, hydrogen, and stress corrosion. It finds that a higher amount of reversed austenite leads to a higher yield-to-tensile strength ratio, increased ductility, and lower hardness. While reversed austenite improves resistance to pitting, intergranular, and stress corrosion, its effect on hydrogen embrittlement remains debated.Additionally, the paper summarizes the formation principles of reversed austenite in martensitic stainless steels and reviews elements influencing its formation, aiming to identify optimal elements and heat treatment methods to increase reversed austenite content. This paper aims to make a summary of the research of experts and scholars in recent years, provide the knowledge foundation for the scholars who have just contacted, and give some reference for the future research direction.

Local Hydrogen Concentration and Distribution in Pd Nanoparticles: An In Situ STEM-EELS Approach.

Local detection of hydrogen concentration in metals is of central importance for many areas of hydrogen technology, such as hydrogen storage, detection, catalysis, and hydrogen embrittlement. A novel approach to measure the hydrogen concentration in a model system consisting of cubic palladium nanoparticles (Pd NPs), with a lateral resolution down to 4nm is demonstrated. By measuring the shift of the Pd bulk plasmon peak with scanning transmission electron microscopy (STEM) combined with energy electron loss spectroscopy (EELS) during in situ hydrogen gas loading and unloading, local detection of the hydrogen concentration is achieved in TEM. With this method, concentration changes inside the NPs at various stages of hydrogenation/dehydrogenation are observed with nanometer resolution. The versatility of in situ TEM allows to link together microstructure, hydrogen concentration, and local strain, opening up a new chapter in hydrogen research.

Effect of Hydrogen on Tensile Properties and Fracture Behavior of Two High-Strength American Petroleum Institute Linepipe Steels

This study explored the influence of hydrogen on the tensile properties and fracture behavior of high-strength API X70 and X80 linepipe steels with bainitic microstructures under varying hydrogen charging conditions. The X70 steel exhibited a ferritic microstructure with some pearlite, while the X80 steel showed a bainitic microstructure and fine pearlite due to the addition of molybdenum. Slow strain rate tests (SSRTs) were conducted using both electrochemical ex situ and in situ hydrogen charging methods subjected to different current densities. The SSRT results showed that in situ hydrogen-charged SSRT, performed at current densities above 1 A/m2, led to more pronounced hydrogen embrittlement compared to ex situ hydrogen-charged SSRT. This occurred because hydrogen was continuously supplied during deformation, exceeding the critical concentration even in the center regions, leading to quasi-cleavage fractures marked by localized cleavage and tearing ridges. Thermal desorption analysis (TDA) confirmed that a greater amount of hydrogen was trapped at dislocations during in situ hydrogen-charged SSRT, intensifying hydrogen embrittlement, even with a shorter hydrogen charging duration. These findings highlight the importance of selecting appropriate hydrogen charging methods and understanding the hydrogen embrittlement behavior of linepipe steels.

Microstructures of Directionally Solidified Nb15Ti55Fe30 Alloy and Its Hydrogen Permeation Properties in the Presence of H2S

Currently, the main limitations of Pd-coated Nb-TiFe dual-phase alloys include insufficient hydrogen permeability, susceptibility to hydrogen embrittlement (HE), and poor tolerance of H2S poisoning. To address these issues, this study proposes a series of improvements. First, a novel Nb15Ti55Fe30 alloy composed of a well-aligned Nb-TiFe eutectic was successfully prepared using directional solidification (DS) technology. After deposition with a Pd catalytic layer, this alloy exhibits high hydrogen permeability of 3.71 × 10−8 mol H2 m−1 s−1 Pa−1/2 at 673 K, which is 1.4 times greater than that of the as-cast counterpart. Second, to improve the H2S corrosion resistance, a new Pd88Au12 catalytic layer was deposited on the surface using a multi-target magnetic control sputtering system. Upon testing in a 100 ppm H2/H2S mixture, this membrane exhibited better resistance to bulk sulfidation and a higher permeance recovery (ca. 58%) compared to pure Pd-coated membrane. This improvement is primarily due to the lower adsorption energies of the former with H2S, which hinders the formation of bulk Pd4S. Finally, the composition region of the Pd-Au catalytic membrane with high comprehensive performance was determined for the first time, revealing that optimal performance occurs at around 12–18 at.% Au. This finding explains how this composition maintains a balance between high H2 permeability and excellent sulfur resistance. The significance of this study lies in its practical solutions for simultaneously improving hydrogen permeability and resistance to H2S poisoning in Nb-based composite membranes.

A deformation-diffusion interactive model to study crack-tip behaviour and predict crack growth rate under fatigue and hydrogen-embrittlement conditions

Hydrogen is accepted as a cleaner and more sustainable energy source, since it carries abundant energy and does not produce any effluent gas from burning when compared to fossil fuels. However, long-term degradation in mechanical properties, attributed to hydrogen embrittlement, is reported for metallic materials exposed to gaseous hydrogen, leading to accelerated crack growth behaviour under fatigue. In this paper, a visco-plastic deformation-diffusion interactive model is developed to study fatigue crack growth behaviour in a nickel-based superalloy under hydrogen-embrittlement condition. In the model, cyclic deformation is described by visco-plasticity constitutive model, while hydrogen diffusion is simulated by a modified form of Fick’s first law of diffusion which can address hydrogen diffusion driven by the hydrostatic stress gradient. In particular, trapped hydrogen, expressed as dependent on both diffusible hydrogen concentration and inelastic strain, is considered in the modelling of hydrogen diffusion. The model also describes the effects of hydrogen concentration on mechanical deformation by considering its influence on the evolution of isotropic hardening as well as on the strain state. Interaction between cyclic deformation and hydrogen diffusion is therefore studied for a crack tip in a compact tension specimen subjected to fatigue and hydrogen attack, showing a strong dependency on both loading frequency and stress intensity factor range. Subsequently, a two-parameter criterion is proposed for fatigue crack growth prediction, which accounts for the contributions of both cyclic deformation and hydrogen diffusion. The predictions show a good agreement with experimental data in terms of crack growth rate under fatigue and hydrogen-embrittlement conditions.

Hydrogen Content Dependence of the Contribution of Dislocation-slip Stability and Carbide Precipitation Morphology to the Hydrogen Embrittlement Property of High-strength Martensitic Steels

Hydrogen Content Dependence of the Contribution of Dislocation-slip Stability and Carbide Precipitation Morphology to the Hydrogen Embrittlement Property of High-strength Martensitic Steels

Hydrogen-induced crack behavior of a precipitation-strengthened Ni50Cr20Co15Al10V5 high entropy alloy

The hydrogen-induced cracking behavior and mechanism of an L12-strengthened Ni50Cr20Co15Al10V5 high entropy alloy was evaluated using the tensile test after hydrogen charging. The microstructures and hydrogen-induced cracks were characterized by electron backscatter diffraction and electron channeling contrast imaging methods. The results revealed that hydrogen decreased the strain hardening rate and induced pronounced cracks, leading to significant degradation in elongation. After deformation, the local strain was concentrated in the precipitate-matrix interfaces. The precipitate-matrix boundary and the interior of precipitates were prone to hydrogen embrittlement, where hydrogen-induced cracks tended to propagate, attributing to the hydrogen-enhanced decohesion mechanism.

Hydrogen embrittlement of a V + Nb-microalloyed high-strength bolt steel subjected to different austenitizing temperatures

Hydrogen embrittlement of a V + Nb-microalloyed high-strength bolt steel subjected to different austenitizing temperatures

A study of hydrogen trapping behaviors in Nb and V carbides in α-Fe matrix by first-principles calculations

The introduction of nanosized carbides (NbC, TiC, VC, etc.) into a matrix is one of the most efficient approaches for improving the hydrogen embrittlement resistance of traditional high strength steels. In the present work, first-principles calculations were used to investigate the characteristics of hydrogen trapping at NbC/bcc-Fe and VC/bcc-Fe interfaces. Hydrogen atoms prefer to occupy the tri2-site in bulk NbC and VC lattices and perfect NbC and VC lattices cannot trap H atoms. H atoms can segregate at perfect NbC/Fe and VC/Fe interfaces, in which the solution energies of the H atoms at the NbC/Fe interfaces are lower. The carbon vacancies at the carbide/Fe interfaces can act as relatively deep hydrogen traps but are unfavorable for formation owing to their high formation energies. Other interstitial sites at interfaces containing carbon vacancies can trap H atoms more strongly than perfect interfaces. Compared with the NbC/Fe interface, it is more probable for H atoms to be trapped by high-density vacancies in the interior of VC carbides once H atoms obtain sufficient energy under certain conditions, eg. at high temperatures.

In-situ hydrogen production from petroleum reservoirs and the associated high temperature hydrogen attack: A review

In-situ hydrogen production from petroleum reservoirs and the associated high temperature hydrogen attack: A review

An analysis of intuitionistic fuzzy sets in risk-based inspection: A case study of hydrogen crack damage in steel tanks under gas pressure

An analysis of intuitionistic fuzzy sets in risk-based inspection: A case study of hydrogen crack damage in steel tanks under gas pressure

Stress corrosion cracking mechanisms in bridge cable steels: Anodic dissolution or hydrogen embrittlement

Two key mechanisms, anodic dissolution, and hydrogen embrittlement, govern the stress corrosion cracking (SCC) in bridge cable steel wires. This study investigates the predominant mechanism influencing the SCC fracture time of bridge cable steel wires through electrochemical methods and thermal desorption analysis (TDA), offering protective measures. It contrasts the impacts of these mechanisms on electrochemical and mechanical properties and fracture morphology. The results show that the main mechanism of SCC in ammonium thiocyanate (NH4SCN) solution is hydrogen embrittlement (HE). Applying an anodic current (50 A/m2) can reduce the hydrogen absorption from 4.99 ppm to 0.2 ppm, and extend the fracture time from 26.1 h to 46.1 h. For the HE type SCC, the corrosion potential of the steel wire does not change with the corrosion time, and the tensile strength and diameter of the steel wire are the almost same as before corrosion. This research provides a theoretical basis for analyzing and protecting bridge cable steel wires against SCC.

Sensitivity of the J-Integral Method for Estimating the Hydrogen Embrittlement of Ferritic-Pearlitic Pipe Steel

Sensitivity of the J-Integral Method for Estimating the Hydrogen Embrittlement of Ferritic-Pearlitic Pipe Steel

Mechanical damage coefficients of corroding reinforcement of an old building based on the residual “effective” area

AbstractCorrosion decreases the metal mass of the rebar, which reduces its bearing section in addition to developing the risk of hydrogen embrittlement of the bars due to the acidity created during active corrosion. To evaluate the residual strength of corroding bars, a framework was proposed in a previous paper to categorize the alternative modes of failure (ductile or brittle), emphasizing the need to calculate first what was named “the effective residual” area to further calculate tensile parameters characterizing the stress–strain curve: yield and tensile strength, modulus of elasticity, and ultimate strain. Using the effective residual area, it is possible to deduce some damage coefficients of each mechanical property by calculating the ratio of corroded/uncorroded condition and deducing if the uncorroded properties of the steel remain or have been degraded by the corrosion process. In the present paper, such an approach has been applied to bars obtained from a historical building around 100 years old. First, stress–strain tests were performed on quasi‐uncorroded and on corroded bars and thereafter, effective residual area is deduced in this case from the weight loss of the bars. With this effective residual area, we then recalculate the mechanical parameters in corrosion conditions and the corresponding damage coefficients.

Insights on formation of oxide layers, corrosion, and hydrogen embrittlement on the Ti2AlNb (1 1 0) surface: Density functional theory study

Ti2AlNb alloys offer good mechanical qualities and promise for use in various applications, such as aero-engines and other industries. However, corrosion and hydrogen embrittlement remain important concerns and limitations for their use. In this work, first-principle density functional theory is used to investigate the adsorption of hydrogen, fluorine and oxygen on the surface of Ti2AlNb (110). The effects of the considered adsorbates on the surface were compared by analysing the adsorption energy, charge density differences, density of states, and work function. The current findings revealed that the adsorption behaviour of all the adsorbates is exothermic and spontaneous due to the negative adsorption energy. More importantly, the effect of Van der Waals forces and dispersion correction was considered, it was found that for all adsorbates the dispersion correction approach exhibited the most stable adsorption energies (EadsDFT-D) than the standard density functional theory (EadsDFT). Thus, the standard DFT underestimates the adsorption energy. Furthermore, it was shown that the adsorption energy strength is dependent on the surface adsorption site, with the Ti-Nb and Al-Nb bridge sites being the most preferred sites for hydrogen, fluorine and oxygen adsorption. Subsequently, it was discovered that oxygen adsorption on the surface of Ti2AlNb (110) was more thermodynamically stable than hydrogen and fluorine. This suggests that the Ti2AlNb surface will likely suffer from oxidation rather than corrosion and hydrogen embrittlement. In addition, surface atoms showed electron-charge depletion, while adsorbates showed charge accumulation. The adsorption caused charge density redistribution and altered the surface work function.

Accelerated stress corrosion cracking of X80 pipeline steel under the combined effects of sulfate-reducing bacteria and hydrostatic pressure

The microbially mediated metal stress corrosion cracking (SCC) mechanisms in deep-sea environments remain unclear, hindering the safe use of deep-sea equipment materials. Hydrostatic pressure facilitated microbiologically influenced corrosion resulting in the pitting depth increase. The stress concentration at the pit bottom induced anodic dissolution (AD), leading to ductile fracture. Hydrostatic pressure and iron sulfides both enhanced the hydrogen evolution reaction (HER). The sulfides produced by SRB metabolism inhibit hydrogen atom recombination, leading to a higher hydrogen permeation current and inducing hydrogen embrittlement (HE) fracture. The combined effect of AD and HE increases the SCC susceptibility of deep-sea pipeline steel.

Effect of Hydrogen Content on the Microstructure, Mechanical Properties, and Fracture Mechanism of Low-Carbon Lath Martensite Steel

The effect of hydrogen content on the microstructure, mechanical properties, and fracture mechanisms of low-carbon lath martensitic steel was investigated using both experimental methods and atomistic modeling. Tensile testing revealed a transition in the fracture behavior with increases in hydrogen concentration. Specifically, at a hydrogen content of 0.44 wppm, a shift from transgranular to intergranular fractures was observed. The most probable cause of hydrogen embrittlement was identified to be HELP-mediated HEDE. As the hydrogen concentration increased, the dislocation density in close-packed planes, such as (111) and (100), was found to rise. The key differences between the hydrogen-free and hydrogen-charged specimens were the localization and density of dislocations, as well as the change in the distribution of slip bands. Atomistic modeling supported these experimental findings, showing that “quasi-cleavage” cracks predominantly initiate at block boundaries with higher local hydrogen accumulation. These results underscore the significant role of hydrogen in modifying both the microstructural characteristics and fracture behavior of low-carbon martensitic steel, with important implications for its performance in hydrogen-rich environments.

Characterizing microstructural changes due to hydrogen embrittlement: Predicting mechanical properties according to hydrogen amount

To prevent the occurrence of severe industrial accidents caused by the hydrogen embrittlement (HE) of austenitic stainless steel, the mechanism of HE based on deformation behavior is identified, and a model equation for predicting the mechanical properties according to hydrogen amount is developed. The mechanical properties included with various amounts of hydrogen are evaluated via a slow strain rate test. Whereas the hydrogen trapping sites remain unchanged regardless of the hydrogen amount, the following vary: the microstructural characterizations formed by HE on the fracture surface, the work-hardening rate behavior with strain-induced martensite, and the phase fraction after fracture. Depending on the amount of hydrogen, either both ductility and brittleness or only brittleness may be observed. Based on these characteristics, the effect of hydrogen on deformation behavior is confirmed. By confirming the two effects of hydrogen on the deformation behavior, the phase fraction after fracture, elongation, and elongation loss are predicted according to the mechanical properties predicted according to hydrogen amount.

Comparative Study of Hydrogen Embrittlement of Tempered Martensitic Steels Containing Ti, Nb and V

Comparative Study of Hydrogen Embrittlement of Tempered Martensitic Steels Containing Ti, Nb and V

Hydrogen Trapping at Fe/Cu Interfaces.

Copper (Cu) in steel production can be a residual element, causing challenges during steel processing, as well as an alloying element, improving corrosion resistance and providing hardenability by nanosized precipitates. For the transition toward a green economy, increased recycling rates in steel production and alternative energy carriers, such as hydrogen, are of vital importance. As hydrogen is known for its embrittling effect on high-strength steels, this work sought to explore possible mitigation strategies for hydrogen embrittlement (HE) with the help of Cu precipitates. Hydrogen trapping at Cu/Fe interfaces following the complex phase transformations in the Cu precipitation sequence from body-centered cubic (bcc) to the so-called 9R structure to face-centered cubic (fcc) was addressed by a series of systematic density functional theory calculations. In combination with thermodynamic calculations, the pressing question regarding which of the precipitate structures was most desirable for the tackling of HE was alluded to. We found that hydrogen trapping at the Cu/Fe interfaces increased from -0.05 to -0.18 eV following the precipitation sequence. Despite this relatively weak hydrogen trapping, which was in the range of dislocations, we showed through thermodynamic calculations that fcc Cu precipitates could still contribute to lowering the risk of triggering the hydrogen-enhanced localized plasticity (HELP) mechanism of HE.