In situ micromechanical testing in environmental scanning electron microscope: A new insight into hydrogen-assisted cracking

Rogne, Bjørn Rune Sørås; Kheradmand, Nousha; Deng, Yun; Barnoush, Afrooz

doi:10.1016/j.actamat.2017.10.037

Cited by 34 publications

(18 citation statements)

References 57 publications

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“…Furthermore, using the sample size and loading type dependence of deformation and dislocation arrangement, additional insights in the environmentally assisted crack propagation can be obtained (for example relating to the phenomena of hydrogen embrittlement [99]). In the case of environmentally assisted crack propagation, in addition to the mentioned characteristic lengths, the extent of the environmentally affected region has to be taken into consideration.…”

Section: Final Remarksmentioning

confidence: 99%

Fracture mechanics of micro samples: Fundamental considerations

2018

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• Fundamental concepts of fracture mechanics are revisited with respect to their applicability in miniaturized experiments • Stress state and notch sharpness in miniaturized samples need to be considered • For size independent fracture toughness values, sample sizes must obey relations to the microstructure and fracture process zone • Different contributions to material toughness can be separated by appropriate experimental design

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Section: Final Remarksmentioning

confidence: 99%

Fracture mechanics of micro samples: Fundamental considerations

2018

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“…As mentioned, the hydrogen diffusion inside the welded joint cannot be in situ measured by the experiment methods, including the traditional test methods [34,35,36,37] and advanced in situ observation technology [38,39,40]. The finite element analysis is probably the only effective method to predict the hydrogen concentration evolution.…”

Section: Introductionmentioning

confidence: 99%

Self-Gathering Effect of the Hydrogen Diffusion in Welding Induced by the Solid-State Phase Transformation

et al. 2019

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The hydrogen diffusion in welding was investigated by using thermal-mechanical-hydrogen diffusion sequential coupled procedures based on finite element method. A self-gathering effect induced by the solid-state phase transformation was discovered. Because of the self-gathering effect, the hydrogen concentration in weld metal was accumulated to a peak value which can be larger than the initial hydrogen concentration in molten pool, and subsequently the hydrogen concentration in heat affect zone was redistributed. In multi-pass welding, the gathered effect not only happened inside a weld pass, but also in the inter-pass, which further increased the sensitivity of the hydrogen-assisted cold cracking. Controlling should be adopted to restrain the hydrogen accumulation. Welding stress evolution during the solid-state phase transformation process had limited effect on the hydrogen diffusion.

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“…In conclusion, Koyama et al [ 21 ] gave an overview of recent progress in microstructure-specific hydrogen mapping techniques. However, the hydrogen diffusion inside the welded joint cannot be in-situ measured by experimental methods including traditional test methods [ 22 , 23 , 24 , 25 ] and advanced in-situ observation technology [ 26 , 27 , 28 ]. Finite element analysis was an effective method to quantitatively predict the change of hydrogen concentration of the welded joint.…”

Section: Introductionmentioning

confidence: 99%

Study on Hydrogen Diffusion Behavior during Welding of Heavy Plate

2020

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For the multi-layer and multi-pass welding process of the heavy plate, the hydrogen diffusion behavior was numerically simulated to study the effect of solid-state phase transition (SSPT) on the hydrogen diffusion in the thickness direction, and the influence of the residual stress-induced diffusion after SSPT. The calculation results were compared with the experimental results. The comparison shows that the distribution of hydrogen concentration in the direction of thickness was in good agreement. The position with the most severe cold cracking sensitivity was located at a 20–30 mm depth from the top surface in this article. After welding, the hydrogen concentration in this position was kept at a high level for a long time under the effect of the size-constraint effect of the heavy plate and the existence of welding residual stress gradient. In addition, the SSPT reduced the residual stress level of weld metal (WM) significantly, increased that of the heat affected zone (HAZ), and the hydrogen was redistributed under the influence of stress. In the process of phase transformation, the parameters of hydrogen diffusion property of the material changed dramatically in a short time, the hydrogen diffusion coefficient increased in order of magnitude, and the solubility decreased in order of magnitude. This directly led to the upward diffusion of hydrogen in WM, and produced a self-gathering effect. For a welded joint of heavy plate, the self-gathering effect between passes was effective in the short-range and ineffective in the long-range.

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In situ micromechanical testing in environmental scanning electron microscope: A new insight into hydrogen-assisted cracking

Cited by 34 publications

References 57 publications

Fracture mechanics of micro samples: Fundamental considerations

Fracture mechanics of micro samples: Fundamental considerations

Self-Gathering Effect of the Hydrogen Diffusion in Welding Induced by the Solid-State Phase Transformation

Study on Hydrogen Diffusion Behavior during Welding of Heavy Plate

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