Direct evaluation of grain boundary hydrogen embrittlement: A micro-mechanical approach

Takahashi, Yoshihiro; Kondo, Hikaru; Asano, Ryuzo; Arai, Shigeo; Higuchi, Kenichi; Yamamoto, Yuta; Muto, Shunsuke; Tanaka, Nobuo

doi:10.1016/j.msea.2016.03.035

Cited by 37 publications

(13 citation statements)

References 25 publications

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“…This dual role of low- grain boundaries was discussed to decrease grain boundary cohesive energy and promote decohesion. More recently, Takahashi et al [205] investigated the local effects of gaseous hydrogen on grain boundary embrittlement in . They used a microsampling technique with nanoindentation inside an environmental TEM, observing different fracture phenomena between charged and H-free samples.…”

Section: Hydrogen Embrittlement Mitigation Strategies and Design Of Nmentioning

confidence: 99%

Understanding and mitigating hydrogen embrittlement of steels: a review of experimental, modelling and design progress from atomistic to continuum

et al. 2018

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Hydrogen embrittlement is a complex phenomenon, involving several lengthand timescales, that affects a large class of metals. It can significantly reduce the ductility and load-bearing capacity and cause cracking and catastrophic brittle failures at stresses below the yield stress of susceptible materials. Despite a large research effort in attempting to understand the mechanisms of failure and in developing potential mitigating solutions, hydrogen embrittlement mechanisms are still not completely understood. There are controversial opinions in the literature regarding the underlying mechanisms and related experimental evidence supporting each of these theories. The aim of this paper is to provide a detailed review up to the current state of the art on the effect of hydrogen on the degradation of metals, with a particular focus on steels. Here, we describe the effect of hydrogen in steels from the atomistic to the continuum scale by reporting theoretical evidence supported by quantum calculation and modern experimental characterisation methods, macroscopic effects that influence the mechanical properties of steels and established damaging mechanisms for the embrittlement of steels. Furthermore, we give an insight into current approaches and new mitigation strategies used to design new steels resistant to hydrogen embrittlement.

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Section: Hydrogen Embrittlement Mitigation Strategies and Design Of Nmentioning

confidence: 99%

Understanding and mitigating hydrogen embrittlement of steels: a review of experimental, modelling and design progress from atomistic to continuum

et al. 2018

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“…GBs are essentially preferential sites for hydrogen trapping or diffusion in both BCC [73] and face-centered cubic (FCC) metals [74,75]; however, it is known that such ability is strongly dependent on the GB properties, such as misorientation angle, coherency or sigma values [74][75][76][77], sometimes changing the behavior of hydrogen-induced crack initiation and propagation related to GBs [73,[77][78][79]. For instance, Rath and Bernstein studied the cracking behavior in pure iron under cathodic hydrogen charging without externally applied stress, and found that only the GBs with misorientation angle greater than 20 degree shows IG cracking [80].…”

Section: Mechanism Of Hydrogen-induced Ig Crack Propagationmentioning

confidence: 99%

Hydrogen-assisted crack propagation in α-iron during elasto-plastic fracture toughness tests

Birenis

Ogawa

Matsunaga

et al. 2019

Materials Science and Engineering: A

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The scope of this thesis is to explore the applications of electron microscopy in the eld of hydrogen embrittlement (HE). The fundamental understanding of HE is still lacking and requires some advanced approaches to improve it. Electron energy-loss spectroscopy (EELS) was tested as a potentially viable technique for indirect hydrogen detection at nano-scale with transmission electron microscope (TEM). Hydrogen trapped at the grain boundaries or dislocations was expected to change electronic structure of local iron atoms in pure Fe specimens as predicted by density functional theory (DFT). Unfortunately, no changes in electronic structure were detected experimentally and the hypothesis was not con rmed due to several possible reasons. Namely, high dose of electrons inducing radiolysis and knock-on damage, and too high background signal. Recently developed direct-detection cameras are suggested as a possible solution for overcoming both of these limitations. This PhD project was quite a journey. Hydrogen embrittlement eld is like a forest-the deeper you go the darker it gets. I am very happy that in the end I found the exit from this forest and managed to reach the goal of the four year project-nishing this thesis. A more exciting part of the journey was the opportunity to stay in Japan for more than six months. There I met some great experts in the eld of hydrogen embrittlement, but more importantly great people who became not only my colleagues, but also friends. I would therefore like to thank my main supervisor, Annett Thøgersen, for providing me with the opportunity to explore the eld of hydrogen embrittlement, for guiding me through the pitfalls and encouraging when I was trapped in one. I also want to acknowledge her organizational skills, which made the trip to Japan possible. My co-supervisors, Øystein Prytz and Amin S. Azar, made an invaluable contribution to my development as a researcher. Their clear explanations and thorough discussions on di cult technical topics helped me a lot to proceed forward and taught me to think and work in a more methodical way, which is an indispensable skill in academia. I would also like to thank the people in the Structural Physics group who were together all along these past four years. In particular for their time spent on assisting me with the microscopes, sharing the knowledge about di erent techniques, doing workouts at the ping-pong table and having quick, two hour long tea/co ee breaks. My only regret for these years is that I didn't spend enough time with you. I am extremely grateful to have met my collaborates from Japan, Hisao Matsunaga, Yuhei Ogawa, Osamu Takakuwa, and Junichiro Yamabe. I felt like by simply being among them I was getting smarter and more disciplined. Without their contributions, this thesis would not be possible. My family deserves a special thanks for supporting me during all these years. They are the ones who taught me determination and that everything is possible if you want it enough. I am extremely proud of having such encouraging, but al...

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“…12,18,19) The load reduction rate with respect to the displacement is regarded as a crack propagation rate with respect to given strain. It turns out from the present microbending test results that the HE crack propagates more easily in the direction parallel to the α-θ interface than normal to the α-θ interface.…”

Section: Microbending Testmentioning

confidence: 99%

Anisotropy in Hydrogen Embrittlement Resistance of Drawn Pearlitic Steel Investigated by <i>in-situ</i> Microbending Test during Cathodic Hydrogen Charging

et al. 2018

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To investigate causes of superior hydrogen embrittlement resistance of drawn pearlitic steel, notched microcantilevers with different notch orientations with respect to the lamellar interface were fabricated by focused ion beam, and microbending tests were conducted in air and during cathodic hydrogen charging by electrochemical nanoindentation. In air, indentation load monotonically increased with increase in indentation displacement, and no crack appeared for any notch orientations. During hydrogen charging, indentation load declined, and a crack appeared. The load reduction with respect to the displacement was larger, and the crack was deeper for the notch parallel to the lamellar interface than that normal to the lamellar interface. Furthermore, stationary cracks in the microcantilevers were observed by scanning electron microscopy and scanning transmission electron microscopy. For the notch parallel to the lamellar interface, a sharp long crack was identified along the lamellar interface. The crack stopped at the position where the cementite lamellae are disconnected. In lattice images, cementite was identified in one side of the crack, and ferrite in another side of the same crack. On the other hand, for the notch normal to the lamellar interface, a blunt short crack was identified. Thus, it was concluded that the ferrite-cementite interface is a preferential crack path, and hydrogen embrittlement resistance in the direction parallel to the lamellar interface is superior to that normal to the lamellar interface. The present results also indicate that directional lamellar alignment of the drawn pearlitic steel suppresses crack propagation in the radial direction of the drawn wire, improving the hydrogen embrittlement resistance in the drawing direction.

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Direct evaluation of grain boundary hydrogen embrittlement: A micro-mechanical approach

Cited by 37 publications

References 25 publications

Understanding and mitigating hydrogen embrittlement of steels: a review of experimental, modelling and design progress from atomistic to continuum

Understanding and mitigating hydrogen embrittlement of steels: a review of experimental, modelling and design progress from atomistic to continuum

Hydrogen-assisted crack propagation in α-iron during elasto-plastic fracture toughness tests

Anisotropy in Hydrogen Embrittlement Resistance of Drawn Pearlitic Steel Investigated by <i>in-situ</i> Microbending Test during Cathodic Hydrogen Charging

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