The interaction of dislocations and hydrogen-vacancy complexes and its importance for deformation-induced proto nano-voids formation in α-Fe

Li, Suzhi; Li, Yonggang; Lo, Yu Chieh; Neeraj, T.; Srinivasan, Rajagopalan; Ding, Xiangdong; Sun, Jun; Liang, Qianhui; Gumbsch, Peter; Li, Ju

doi:10.1016/j.ijplas.2015.05.017

Cited by 160 publications

(85 citation statements)

References 74 publications

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“…Hydrogen is positioned in interstitial sites [24] and reduces the atomic cohesive strength by creating micro-defects. Recent research [25] on the fundamental work of Fukai andŌkuma [26] showed that hydrogen atoms in interstitial positions can interact with vacancies and stabilize them by forming hydrogen-vacancy complexes. The number of hydrogen-vacancy complexes is increased during deformation of the material, whereas with time they tend to agglomerate and act as nuclei for the formation of nano-voids [25].…”

Section: Resultsmentioning

confidence: 99%

“…Recent research [25] on the fundamental work of Fukai andŌkuma [26] showed that hydrogen atoms in interstitial positions can interact with vacancies and stabilize them by forming hydrogen-vacancy complexes. The number of hydrogen-vacancy complexes is increased during deformation of the material, whereas with time they tend to agglomerate and act as nuclei for the formation of nano-voids [25]. In any case, the increase in the concentration and size of these defects leads to strain hardening and subsequently increases the surface hardness of the alloy.…”

Section: Resultsmentioning

confidence: 99%

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The Effect of Cold Rolling on the Hydrogen Susceptibility of 5083 Aluminum Alloy

Georgiou

Celis

Panagopoulos

2017

Metals

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This work focuses in investigating the effect of cold deformation on the cathodic hydrogen charging of 5083 aluminum alloy. The aluminium alloy was submitted to a cold rolling process, until the average thickness of the specimens was reduced by 7% and 15%, respectively. A study of the structure, microhardness, and tensile properties of the hydrogen charged aluminium specimens, with and without cold rolling, indicated that the cold deformation process led to an increase of hydrogen susceptibility of this aluminum alloy.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

The Effect of Cold Rolling on the Hydrogen Susceptibility of 5083 Aluminum Alloy

Georgiou

Celis

Panagopoulos

2017

Metals

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“…Because of its small size, high mobility and attractive interaction with open volume defects hydrogen seems to be a typical example of a defactant. Segregated hydrogen stabilizes open volume defects and increases their concentration [7][8][9]. For example the equilibrium concentration of vacancies becomes enhanced by many orders of magnitude in metals containing absorbed hydrogen [10,11].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Defects in Titanium Created by Hydrogen Charging

et al. 2017

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Hydrogen interaction with vacancies in α-Ti was investigated employing positron lifetime spectroscopy combined with ab initio theoretical modeling of vacancy-hydrogen complexes. Ab initio modeling revealed that multiple hydrogen atoms up to 7 can be trapped at vacancies in the α-Ti lattice. Trapped H atoms are located close to the nearest neighbor tetrahedral sites around the centre of vacancy. Lifetimes of positrons trapped at vacancies associated with various numbers of hydrogen atoms were calculated. Positron lifetime measurement of H-loaded α-Ti samples revealed that phase transition into the hydride phase introduced dislocations. Vacancies were created by H loading as well and agglomerated into small vacancy clusters.

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“…A second vacancy swept into the same location was shown to lead to the formation of a two-vacancy/one-hydrogen cluster. From these two studies, and the knowledge that vacancy-hydrogen interactions in Fe (and many other metals) are attractive, such that the 25 general reaction nV + mH → V n H m is energetically favorable, it was speculated that the observed nanovoid growth in steels is due to sequential vacancy sweeping by dislocations, trapping by hydrogen, and subsequent diffusion and coalescence of vacancies and voids [17]. These findings present an intriguing effect of Hydrogen that merits a more-complete study of the interactions among vacancies, hydrogen, and edge dislocations in bcc Fe.…”

Section: Introductionmentioning

confidence: 99%

“…The potential used in the simulations is essentially identical to that used in the recent study of V-H-dislocation interactions [17]. To assess the validity of this potential for our studies involving Fe, H, and V, we have made comparisons of various energies as well as the structure of the core of the dislocation with and 75 without a vacancy with the energies and structures obtained via the quantum-mechanical/molecular-mechanics method (QM/MM) method.…”

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confidence: 99%

Hydrogen–vacancy–dislocation interactions inα-Fe

Tehranchi

Zhang

Lü

2016

Modelling Simul. Mater. Sci. Eng.

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Abstract. Atomistic simulations of the interactions between dislocations, hydrogen atoms, and vacancies are studied to assess the viability of a recently-proposed mechanism for the formation of nanoscale voids in Fe-based steels in the presence of hydrogen. QM/MM calculations confirm EAM simulations showing that individual vacancies on the compressive side of an edge dislocation can be transported with the dislocation as it glides. EAM simulations then show, however, that vacancy clusters in the glide plane of an approaching dislocation are annihilated or reduced in size by the creation of a double-jog/climb process that is driven by the huge reduction in energy accompanying vacancy annihilation. The effectiveness of annihilation/reduction processes is not reduced by the presence of hydrogen in the vacancy clusters since V-H cluster binding energies are much lower than the vacancy formation energy, except at very hydrogen content in the cluster. Analysis of a range of configurations indicates that Hydrogen plays no special role in stabilizing nanovoids. Experimental observations of nanovoids on the fracture surfaces of steels must be due to as-yet undetermined processes.

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The interaction of dislocations and hydrogen-vacancy complexes and its importance for deformation-induced proto nano-voids formation in α-Fe

Cited by 160 publications

References 74 publications

The Effect of Cold Rolling on the Hydrogen Susceptibility of 5083 Aluminum Alloy

The Effect of Cold Rolling on the Hydrogen Susceptibility of 5083 Aluminum Alloy

Characterization of Defects in Titanium Created by Hydrogen Charging

Hydrogen–vacancy–dislocation interactions inα-Fe

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