Effects of hydrogen on fatigue-crack propagation in steels

Murakami, Yukitaka; Ritchie, Robert O.

doi:10.1533/9780857093899.2.379

Cited by 11 publications

(4 citation statements)

References 49 publications

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“…This can be explained by the fact that they are formed on the surface under the conditions of fatigue fracture and then, most likely, damaged due to the effect of crack closure observed in the course of contact of the crack faces in a loading cycle. We also note that the depth of fatigue striations on the fracture surface attains 30 nm [15]. The opening displacement of the crack faces under axial tension is also insignificant.…”

Section: Results Of Fractographic Investigationsmentioning

confidence: 70%

Fractographic Features of the Fatigue Fracture of Nitinol Alloy

et al. 2020

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We study the macro-and microfractographic features of the mechanism of initiation and propagation of fatigue cracks in the nitinol alloy after its testing for low-cycle fatigue and analyze possible influence of the structural and phase transformations caused by the cyclic deformation of nitinol on the fractographic features of its fatigue fracture. Thus, almost parallel transcrystalline facets of brittle cleavage located in almost mutually perpendicular planes along the entire length of martensite crystals are observed within the boundaries of separate grains (first of all, in the early stages of fracture). The signs of shallow fatigue striations are detected (but rarely) in the zone of the stable growth of the fatigue crack. The spacing of these striations approximately corresponds to a crack-growth rate of 8 ⋅10 7 m/cycle. It is suggested that the deformation transformation of austenite into martensite can also distort the classical deformation mechanism of formation of the fatigue striations. In the zones of fractures with uncontrolled crack growth, the elements of ductile pit topography are predominant, which is typical of the fracture surfaces of specimens destroyed under active loading.

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Section: Results Of Fractographic Investigationsmentioning

confidence: 70%

Fractographic Features of the Fatigue Fracture of Nitinol Alloy

et al. 2020

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“…These mechanisms describe the HE effect in terms of different aspects ranging from chemical bonding up to microstructure level. A systematic review has been established by Murakami et al [19] regarding the H effect on the fatigue crack propagation in steels.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen-assisted fatigue crack growth in ferritic steels – a fractographic study

et al. 2018

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Abstract. Fatigue crack growth (FCG) behavior of a Fe-3wt.%Si ferritic alloy under different environmental conditions using in-situ electrochemical (cathodic) hydrogen (H) charging has been investigated. Three frequencies have been applied. Results clearly show that the FCG rate increased by a factor spanning from 20 to 1000 times, depending on the loading frequencies, when compared to the reference test in air. Lower frequency leads to higher FCG rate. A comprehensive fractographic analysis was carried out: the area fraction of different fracture surface features was measured and taken into statistical analysis. Based on these investigations, the possible mechanisms of H-enhanced FCG are discussed. Similar tests in high-pressure H gas from other studies were also compared and discussed. These results give a preliminary understanding of H effect in fatigue crack propagation procedure in ferritic alloys.

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“…The degradation of material performances exposed to a hydrogen-containing medium can furthermore be amplified in presence of a crack-like defect under cyclic loading. Indeed, it is well established that hydrogen atoms can interact with the cyclic crack tip deformation and the induced damage processes to substantially enhance the Fatigue Crack Growth Rate (FCGR) [14][15][16]. The issue of hydrogen embrittlement has recently received a renewed attention in the perspective of the development of hydrogen as a clean energy carrier.…”

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confidence: 99%