Statistical analysis of the low-temperature α peak of the internal friction in iron single crystals

Нацик, В. Д.; Pal‐Val, P. P.; Pal-Val, L.N.; Semerenko, Yu. A.

doi:10.1063/1.1306411

Cited by 8 publications

(5 citation statements)

References 15 publications

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“…found by the Tikhonov regularization method has a maximum in the region of 0.04 eV corresponding to the -peak of acoustic absorption and largely coincides with the quasi-Gaussian function   G P U empirically selected in[3] (Fig.2).In this case, the position of the maximum of the   T P U depends on the structural state of the sample. This fact numerically and qualitatively correlates with the conclusions of[3] about the change in the effective value of change in the statistical scatter characterized by the dispersion parameter D (Table…”

supporting

confidence: 69%

“…in the region of 14-16 K (at an oscillation frequency sample 88 kHz). In [3] these features were not found experimentally, which may be associated with a significant broadening of the main relaxation resonance at a temperature of  54 К. However, in one form or another, the '-peak was repeatedly observed by various…”

Section:      mentioning

confidence: 91%

“…In [3], it was suggested that the energy spectrum of low-temperature acoustic relaxation in iron can be described by the quasi-Gaussian distribution function Energy Activation Spectrum of Low-Temperature Acoustic Relaxation...…”

Section: Eejp 2 (2021)mentioning

confidence: 99%

“…It was shown in [17], [18] that the '-peak should be characterized by the same period of attempts as the -peak and have a value of the order of 10 -11 s. In order to detect the '-peak in Fe single crystals of the <731> orientation, additional experimental studies were carried out in [4]. A sample in the form of a thin plate was made from the same single crystal as in [3]. The acoustic properties of this sample were studied in the temperature range 4.5-150 K. It was found that in the undeformed sample  and ' peaks are not observed, deformation leads to the appearance of -peak localized at 35 K and its ' satellite at a temperature of 13 K. Subsequent annealing at 320 K leads to a decrease in the height of the  peak, narrowing and shifting to lower temperatures, while the '-peak becomes more pronounced.…”

Section: Eejp 2 (2021)mentioning

confidence: 99%

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Energy Activation Spectrum of Low-Temperature Acoustic Relaxation in High-Purity Iron Single Crystal. Solution of the Inverse Problem of Mechanical Spectroscopy by the Tikhonov Regularization Method

2021

EEJP

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When studying the temperature dependences of the acoustic absorption and the modulus of elasticity, absorption peaks are often observed, which correspond to the characteristic step on the temperature dependence of the modulus of elasticity. Such features are called relaxation resonances. It is believed that the occurrence of such relaxation resonances is due to the presence in the structure of the material of elementary microscopic relaxors that interact with the studied vibrational mode of mechanical vibrations of the sample. In a sufficiently perfect material, such a process is characterized by a relaxation time τ, and in a real defective material by a relaxation time spectrum P(τ). Most often such relaxation processes have a thermally activated character and the relaxation time τ(T) is determined by the Arrhenius ratio τ(T)=τ0exp(U0/kT), and the characteristics of the process will be U0 - activation energy, τ0 - period of attempts, Δ0 - characteristic elementary contribution of a single relaxator to the dynamic response of the material and their spectra. In the low temperatures region the statistical distribution of parameters τ0 and Δ0 can be neglected with exponential accuracy, and the relaxation contribution to the temperature dependences of absorption and the dynamic elasticity modulus of the material will be determined only by the activation energy spectrum P(U) of microscopic relaxors. The main task of mechanical spectroscopy in the analysis of such relaxation resonances is to determine U0, τ0, Δ0 and P(U). It is shown, that the problem of recovering of spectral function P(U) of acoustic relaxation of a real crystal can be reduced to the solving of the Fredholm integral equation of the first kind with an approximately known right part and concerns to a class of ill-posed problems. The method based on Tikhonov regularizing algorithm for recovering P(U) from experimental temperature dependences of absorption or elasticity module is offered. It is established, that acoustic relaxation in high-purity iron single crystal in the temperature range 5-100 K is characterized by two-modes spectral function P(U) with maxima at 0.037 eV and 0.015 eV, which correspond to the a-peak and its a' satellite.

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supporting

confidence: 69%

Section:      mentioning

confidence: 91%

Section: Eejp 2 (2021)mentioning

confidence: 99%

Section: Eejp 2 (2021)mentioning

confidence: 99%

See 2 more Smart Citations

Energy Activation Spectrum of Low-Temperature Acoustic Relaxation in High-Purity Iron Single Crystal. Solution of the Inverse Problem of Mechanical Spectroscopy by the Tikhonov Regularization Method

2021

EEJP

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“…Анализ температуры локализаöии и ôормы пиков поглощения по методике [24], последовательно развитой в [24,[31][32][33][34][35][36] позволяет утверждать, что зарегистрированные релаксаöионные резонансы обусловлены системой релаксаторов дебаевского типа с активаöионными параметрами U 0 ≈ 0,06 эВ и τ 0 ≈ 5⋅10 −10 с для P 1 и U 0 ≈ 0,14 эВ и τ 0 ≈ 5⋅10 −10 с для P 2 . Íаблюдаемые отличия акустических свойств изученных сплавов, вероятно, связаны с наличием в сплаве (I) дисперсных включений карбида ниобия, являющихся эôôективными стопорами, существенно тормозящими дислокаöионную динамику в изученном интервале температур.…”

Section: Tableunclassified

Physical-Mechanical Properties of the 54.6Ni–11Fe–30Cr–3.5Nb–0.5Ti–0.4C and 58Ni–11Fe–30Cr–0.5Nb–0.5Ti Alloys in the Low-Temperature Region

Semerenko¹,

Yushchenko²,

Tabachnikova³

et al. 2018

Metallofiz. Noveishie Tekhnol.

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В области температур 4,2-400 К впервые изучены механические и акустические свойства новых никелевых сплавов 54,6Ni-11Fe-30Cr-3,5Nb-0,5Ti-0,4C и 58Ni-11Fe-30Cr-0,5Nb-0,5Ti. Показано, что в данном интервале температур эти сплавы обладают стабильной структурой и достаточно высокими показателями прочности и пластичности.

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Low-temperature α peak of the internal friction in niobium and its relation to the relaxation of kinks in dislocations

Нацик

Pal‐Val

Pal-Val

et al. 2001

Low Temperature Physics

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The influence of impurities on the parameters of the α peak of the internal friction in single-crystal and polycrystalline niobium is investigated; the internal friction is recorded in the temperature range 200–250 K at a vibrational frequency of ≈80 kHz. It is found that increasing the purity of the samples leads to an increase of the peak location temperature and to an increase of its width and amplitude. The structural sensitivity of this peak was observed previously in a study of the influence on this peak of a preliminary plastic deformation, thermocycling, and low-temperature recovery. A statistical description of the whole set of experimental data is proposed, which takes into account the dependence of the activation energy and attempt period on the impurity concentration and on the characteristic value and statistical scatter of the internal stresses. A new algorithm is developed for analyzing the experimental data to obtain empirical estimates for the values of the activation energy, its variance, the attempt period, and relaxation strength for the different structural states of the samples. It is shown that the α peak is a consequence of the resonant interaction of elastic vibrations with the thermally activated nucleation of kink pairs on dislocation segments lying in the valleys of the Peierls potential relief. Empirical estimates are obtained for the values of the main parameters characterizing this process. It is found that the properties of the α peak in niobium are in qualitative agreement with Engelke’s theory of the nucleation and relaxation of dislocation kinks.

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Statistical analysis of the low-temperature α peak of the internal friction in iron single crystals

Cited by 8 publications

References 15 publications

Energy Activation Spectrum of Low-Temperature Acoustic Relaxation in High-Purity Iron Single Crystal. Solution of the Inverse Problem of Mechanical Spectroscopy by the Tikhonov Regularization Method

Energy Activation Spectrum of Low-Temperature Acoustic Relaxation in High-Purity Iron Single Crystal. Solution of the Inverse Problem of Mechanical Spectroscopy by the Tikhonov Regularization Method

Physical-Mechanical Properties of the 54.6Ni–11Fe–30Cr–3.5Nb–0.5Ti–0.4C and 58Ni–11Fe–30Cr–0.5Nb–0.5Ti Alloys in the Low-Temperature Region

Low-temperature α peak of the internal friction in niobium and its relation to the relaxation of kinks in dislocations

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