Hydrogen-enhanced fatigue crack growth in a single-edge notched tensile specimen under in-situ hydrogen charging inside an environmental scanning electron microscope

Wan, Di; Deng, Yun; Meling, Jan Inge Hammer; Alvaro, Antonio; Barnoush, Afrooz

doi:10.1016/j.actamat.2019.03.032

Cited by 61 publications

(26 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Single-edge notched specimens (gauge length 10 mm and width 4 mm; 90° V-notch with a depth of 0.5 mm) were loaded using a Kammrath and Weiss tensile module inside the environmental scanning electron microscope (initial global strain rate 10 -4 s -1 ), during which the plasma phase was ignited and continuously injected by an Evactron Model 25 Zephyr plasma source (XEI Scientific) using pure H gas as the process gas. More details about the H-plasma charging can be found elsewhere 46,47 . Although the H influence on the macroscopic tensile properties is difficult to detect with the current H-plasma charging set-up (partial pressure of the plasma phase is only around 40 Pa; Supplementary Note 3), this charging method provides a distinct contamination-free condition that is particularly useful for revealing detailed features of fracture surfaces.…”

Section: Methodsmentioning

confidence: 99%

Chemical heterogeneity enhances hydrogen resistance in high-strength steels

et al. 2021

Self Cite

View full text Add to dashboard Cite

The antagonism between strength and resistance to hydrogen embrittlement in metallic materials is an intrinsic obstacle to the design of lightweight yet reliable structural components operated in hydrogen-containing environments. Economical and scalable microstructural solutions to this challenge must be found. Here, we introduce a counterintuitive strategy to exploit the typically undesired chemical heterogeneity within the material’s microstructure that enables local enhancement of crack resistance and local hydrogen trapping. We use this approach in a manganese-containing high-strength steel and produce a high dispersion of manganese-rich zones within the microstructure. These solute-rich buffer regions allow for local micro-tuning of the phase stability, arresting hydrogen-induced microcracks and thus interrupting the percolation of hydrogen-assisted damage. This results in a superior hydrogen embrittlement resistance (better by a factor of two) without sacrificing the material’s strength and ductility. The strategy of exploiting chemical heterogeneities, rather than avoiding them, broadens the horizon for microstructure engineering via advanced thermomechanical processing.

show abstract

Section: Methodsmentioning

confidence: 99%

Chemical heterogeneity enhances hydrogen resistance in high-strength steels

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…The defectant theory proposed by Kirchheim [9] based on thermodynamics calculations also provides a theoretical basis for the reduction of the dislocation formation energy in the presence of H segregation. On the other hand, H is reported to suppress the dislocation movement [10,11]. High dislocation density formed beneath the indenter tip along with the H suppression effect holds the formed dislocations in a confined area beneath the indent, resulting in the hardness enhancement.…”

Section: Precipitation Effect On Hardness and Plasticity Onsetmentioning

confidence: 99%

The Effect of Hydrogen on the Nanoindentation Behavior of Heat Treated 718 Alloy

Stenerud

Hajilou

Olsen

et al. 2020

Metals

Self Cite

View full text Add to dashboard Cite

In this study, the effect of precipitates on the surface mechanical properties in the presence of hydrogen (H) is investigated by in situ electrochemical nanoindentation. The nickel superalloy 718 is subjected to three different heat treatments, leading to different sizes of the precipitates: (i) solution annealing (SA) to eliminate all precipitates, (ii) the as-received (AR) sample with fine, dispersed precipitates, and (iii) the over-aged (OA) specimen with coarser precipitates. The nanoindentation is performed using a conical tip, and a new method of reverse imaging is employed to calculate the nano-hardness. The results show that the hardness of the SA sample is significantly affected by H diffusion. However, it could be recovered by removing the H from its matrix by applying an anodic potential. Since the precipitates in the OA and AR samples are different, they are influenced by H differently. The hardness increase for the OA sample is more significant in −1200mV, while for the AR specimen, the H is more effective in −1500mV. In addition, the pop-in load is reduced when the samples are exposed to cathodic charging, and it cannot be fully recovered by switching to an anodic potential.

show abstract

“…On the other hand, more functional accessories could also be developed to solve complex physical/chemical processes which is useful in modern materials science (e.g., the electric/magnetic field assisted sintering process) In addition, a wise combination of three working modes (HiVac, LoVac, and ESEM) may create extra possibilities in realizing novel experimental techniques through rational design. Wan et al have adopted an innovative method to directly observe the effect of hydrogen (H) on fatigue crack growth behavior of pre‐cracked single‐edge notched tensile (SENT) specimen . They performed in situ H‐plasma charging on the SENT in the low vacuum environment in ESEM, and then imaged it in HiVac mode when the H‐plasma was switched off (the normal GSED cannot work in H‐plasma).…”

Section: Summary and Prospectmentioning

confidence: 99%

Applications of ESEM on Materials Science: Recent Updates and a Look Forward

et al. 2019

View full text Add to dashboard Cite

The microscopic understanding of materials relies on the development of microscopy. Historically, the technological evolution from optical microscopes to electron microscopes has directly stimulated many discoveries of new physical and chemical fundamentals as well as advanced materials. Scanning electron microscopy (SEM) is, undoubtedly, the most widely used tool for microscopic characterization in modern materials science. Especially, the incorporation of a gas pressure around the sample area of conventional SEM, i.e., the environmental scanning electron microscope (ESEM), has opened new possibilities in observing samples in their natural states, leading to unprecedented chances for studying the details of biological, organic, and hydrated samples. What is more, in recent years, in situ ESEM studies concerning materials change and chemical reactions have played a more important role in the field of materials science. Herein, the recent applications of ESEM in materials science are comprehensively reviewed, in terms of common static observations for various materials and in situ investigations of dynamic processes in controlled experimental environments. Moreover, the problems concerning state‐of‐the‐art ESEM experiments are discussed, as well as possible solutions. Looking forward, the rapid developments on instrumentation and fundamental science of ESEM can bring a clear vision of materials in the near future.

show abstract

Hydrogen-enhanced fatigue crack growth in a single-edge notched tensile specimen under in-situ hydrogen charging inside an environmental scanning electron microscope

Abstract: Hydrogen-enhanced fatigue crack growth in a single-edge notched tensile specimen under in-situ hydrogen charging inside an environmental scanning electron microscope, Acta Materialia,

Cited by 61 publications

References 57 publications

Chemical heterogeneity enhances hydrogen resistance in high-strength steels

Chemical heterogeneity enhances hydrogen resistance in high-strength steels

The Effect of Hydrogen on the Nanoindentation Behavior of Heat Treated 718 Alloy

Applications of ESEM on Materials Science: Recent Updates and a Look Forward

Contact Info

Product

Resources

About