Dislocation modeling and acoustic emission observation of alternating ductile/brittle events in Fe-3wt%Si crystals

Lii, Mirng-Ji; Chen, X. F.; Katz, Y.; Gerberich, William W

doi:10.1016/0956-7151(90)90255-f

Cited by 93 publications

(34 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many theories have been proposed to explain this phenomenon including hydrogen-enhanced localized plasticity mechanism, [1][2][3][4] hydrogen-enhanced decohesion mechanism [5][6][7] and hydrogen-enhanced vacancies and nanovoids coalescence mechanism. [8][9][10][11] Among these explanations, there is consensus in that mobile hydrogen causes degradation in steels.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Traps and Hydrogen Induced Cracking in 20CrMo Steel

Zhu

Yao

et al. 2017

ISIJ Int.

View full text Add to dashboard Cite

The hydrogen trapping sites of commercial 20CrMo steel samples with electrochemically charged hydrogen were characterized by thermoelectric power (TEP) and scanning Kelvin probe force microscope (SKPFM). A surface potential drop of about 190 mV was found for the globular MnS inclusion and 150 mV for the elongated one due to the hydrogen absorption of MnS inclusions. Similar to thermal desorption measurement, TEP is a potential method in analyzing hydrogen traps of solid solution, dislocations and irreversible traps. The fracture morphology and hydrogen induced cracking can be explained by combined hydrogen embrittlement mechanisms. Although hydrogen induced cracks are found to initiate at the elongated inclusions, only longitudinal cracks were observed in this study which is not detrimental to the embrittlement.

show abstract

Section: Introductionmentioning

confidence: 99%

Hydrogen Traps and Hydrogen Induced Cracking in 20CrMo Steel

Zhu

Yao

et al. 2017

ISIJ Int.

View full text Add to dashboard Cite

show abstract

“…Among deleterious effects of hydrogen, ductility loss [8][9][10] is a well-known phenomenon. Hydrogen-induced degradation in fracture toughness, [11][12][13] fatigue strength, and fatigue crack growth properties [14][15][16][17][18][19][20] has also caused concern in various industrial sectors. With respect to the relationship between hydrogen and microstructure, localized plasticity due to hydrogen-enhanced dislocation mobility [3][4][5][21][22][23][24][25][26] and crystallographic slip localization by hydrogen [27][28][29] have also attracted considerable attention in the field of materials science.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Effect against Hydrogen Embrittlement

Murakami

Kanezaki

Mine

2010

Metall Mater Trans A

179

View full text Add to dashboard Cite

The well-known term ''hydrogen embrittlement'' (HE) expresses undesirable effects due to hydrogen such as loss of ductility, decreased fracture toughness, and degradation of fatigue properties of metals. However, this article shows, surprisingly, that hydrogen can have an effect against HE. A dramatic phenomenon was found in which charging a supersaturated level of hydrogen into specimens of austenitic stainless steels of types 304 and 316L drastically improved the fatigue crack growth resistance, rather than accelerating fatigue crack growth rates. Although this mysterious phenomenon has not previously been observed in the history of HE research, its mechanism can be understood as an interaction between hydrogen and dislocations. Hydrogen can play two roles in terms of dislocation mobility: pinning (or dragging) and enhancement of mobility. Competition between these two roles determines whether the resulting phenomenon is damaging or, unexpectedly, desirable. This finding will, not only be the crucial key factor to elucidate the mechanism of HE, but also be a trigger to review all existing theories on HE in which hydrogen is regarded as a dangerous culprit.

show abstract

“…In this case crack extension proceeds via individual bond breakings, a series of thermally activated events of kink-pair formation and lateral kink migration along the front. It is of interest to point out the crack front mobility is not only controlled by kinks at the atomic size scale as demonstrated in this work, acoustic emission and fractographic measurements have indicated the crack advancement at the mesoscopic scale is also governed by the kink mechanism which involves a process of unzipping along the crack front (W.W. Gerberich, private communication [29]). The fact that a kink mechanism appears to play a central role in crack front mobility raises an interesting question of the implications of structural similarity between the crack front, acting as the core of a sharp crack, and the core of a dislocation, both being "line defects" in a crystal lattice.…”

Section: Probing Crack Front Extension Through Reaction Pathway Samplingmentioning

confidence: 97%

Multiscale Materials Modelling: Case Studies at the Atomistic and Electronic Structure Levels

Silva¹,

Först²,

et al. 2007

ESAIM: M2AN

View full text Add to dashboard Cite

Abstract.Although the intellectual merits of computational modelling across various length and time scales are generally well accepted, good illustrative examples are often lacking. One way to begin appreciating the benefits of the multiscale approach is to first gain experience in probing complex physical phenomena at one scale at a time. Here we discuss materials modelling at two characteristic scales separately, the atomistic level where interactions are specified through classical potentials and the electronic level where interactions are treated quantum mechanically. The former is generally sufficient for dealing with mechanical deformation at large strain, whereas the latter is necessary for treating chemical reactions or electronic transport. We will discuss simulations of defect nucleation using molecular dynamics, the study of water-silica reactions using a tight-binding approach, the design of a semiconductor-oxide interface using density functional theory, and the analysis of conjugated polymer in molecular actuation using Hartree-Fock calculations. The diversity of the problems discussed notwithstanding, our intent is to lay the groundwork for future problems in materials research, a few will be mentioned, where modelling at the electronic and atomistic scales are needed in an integrated fashion. It is in these problems that the full potential of multiscale modelling can be realized.Mathematics Subject Classification. 74A25, 74A45, 74F25, 74M05, 81V55.

show abstract

Dislocation modeling and acoustic emission observation of alternating ductile/brittle events in Fe-3wt%Si crystals

Cited by 93 publications

References 21 publications

Hydrogen Traps and Hydrogen Induced Cracking in 20CrMo Steel

Hydrogen Traps and Hydrogen Induced Cracking in 20CrMo Steel

Hydrogen Effect against Hydrogen Embrittlement

Multiscale Materials Modelling: Case Studies at the Atomistic and Electronic Structure Levels

Contact Info

Product

Resources

About