Core diffusion, unpinning and the Snoek-Köster relaxation

Ritchie, I.G.

doi:10.1016/0036-9748(82)90344-1

Cited by 20 publications

(29 citation statements)

References 17 publications

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“…The temperature of the crystal was then maintained below 1 K so that it remained completely solid for all of the elastic measurements. This was important because small liquid regions would have trapped 3 He impurities at low temperature, leading to temperature variations of the total amount of 3 He in the crystal.…”

Section: Methodsmentioning

confidence: 99%

“…The concentration of impurities near a dislocation is modified from the bulk concentration by a factor exp [−E B /T ], where E B is the binding energy. 26 In solid 4 He, 3 He impurities are only weakly bound to dislocations, and it is possible to break a network link away from bound 3 He atoms at high stress.…”

Section: Dislocations Inmentioning

confidence: 99%

“…If one starts at a high oscillating stress amplitude σ so that the network links are free of bound 3 He, the distribution of network lengths can be inferred from the shear modulus measured while decreasing σ. This argument is analogous to the one made by Iwasa in the context of torsional oscillator experiments.…”

Section: Dislocations Inmentioning

confidence: 99%

“…14 The only impurity is 3 He, whose concentration can be lowered far below 1 ppm. 15 As a consequence, elastic measurements in 4 He crystals are extremely sensitive probes of interactions between dislocations and either highly diluted impurities or thermal phonons.…”

Section: Introductionmentioning

confidence: 99%

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Dislocation networks in4He crystals

et al. 2014

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The mechanical behavior of crystals is dominated by dislocation networks, their structure and their interactions with impurities or thermal phonons. However, in classical crystals, networks are usually random with impurities often forming non-equilibrium clusters when their motion freezes at low temperature. Helium provides unique advantages for the study of dislocations: crystals are free of all but isotopic impurities, the concentration of these can be reduced to the ppb level, and the impurities are mobile at all temperatures and therefore remain in equilibrium with the dislocations. We have achieved a comprehensive study of the mechanical response of 4 He crystals to a driving strain as a function of temperature, frequency and strain amplitude. The quality of our fits to the complete set of data strongly supports our assumption of string-like vibrating dislocations. It leads to a precise determination of the distribution of dislocation network lengths and to detailed information about the interaction between dislocations and both thermal phonons and 3 He impurities. The width of the dissipation peak associated with impurity binding is larger than predicted by a simple Debye model, and much of this broadening is due to the distribution of network lengths.

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Section: Methodsmentioning

confidence: 99%

Section: Dislocations Inmentioning

confidence: 99%

Section: Dislocations Inmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dislocation networks in4He crystals

et al. 2014

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“…SK relaxation which is located well above the Snoek peak in bcc metals is generated by the movement of dislocation segments dragging along with them the Cottrell cloud of FIAs. The exact mechanism of SK relaxation has remained for a long time a controversial issue [2, 6,[14][15][16]. Recently, however, a new insight into the problem has been provided by the application of the coupling model [8, [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Snoek-Köster Relaxation. New Insights - New Paradigms

Magalas

1996

J. Phys. IV France

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The Potential of the Internal Friction Technique to Evaluate the Role of Vacancies and Dislocations in the Hydrogen Embrittlement of Steels

Vandewalle

Konstantinović

Depover

et al. 2021

steel research int.

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Hydrogen embrittlement of steels is known to have considerable impact in many engineering sectors. To be able to mitigate the hydrogen embrittlement problem, a profound comprehension of the interaction of hydrogen with the steel microstructure is required. Especially the interaction of hydrogen with dislocations and vacancies is very relevant as these defects are known to play an important role in hydrogen embrittlement. At present, thermal desorption spectroscopy is mostly used to study hydrogen–defect interactions. However, information obtained solely by this technique is insufficient to obtain a full understanding of the interaction of hydrogen with these defects in the steel microstructure. Herein, the use of internal friction, as a complementary technique to thermal desorption spectroscopy, to reveal the interaction of hydrogen with dislocations and vacancies, is reviewed based on the present understanding in the literature. Furthermore, the opportunities to use internal friction to characterize the interaction between hydrogen and these defects and to give more insight into the hydrogen embrittlement mechanism are discussed. It is demonstrated that internal friction has not yet been used to its full potential for this purpose, although it entails the opportunity to develop fundamental insights into the hydrogen embrittlement phenomenon.

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Core diffusion, unpinning and the Snoek-Köster relaxation

Cited by 20 publications

References 17 publications

Dislocation networks in4He crystals

Dislocation networks in4He crystals

Snoek-Köster Relaxation. New Insights - New Paradigms

The Potential of the Internal Friction Technique to Evaluate the Role of Vacancies and Dislocations in the Hydrogen Embrittlement of Steels

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