Internal Friction of Metallic Glasses : Mechanisms and Conditions of their Realization

Khonik, V. A.

doi:10.1051/jp4:19968128

Cited by 9 publications

(5 citation statements)

References 8 publications

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“…Micron-scale metallic glass resonators have been fabricated as hemispherical shells [10] and as cantilevers [9]. In addition, strains in the range from 10 −7 to 10 −4 have been used in measurements of internal friction in metallic glass resonators [44]. Our results emphasize that nano-sized metallic glass resonators operating in the small strain regime regime (e.g.…”

Section: Methods To Increase Kr and Enhance Qmentioning

confidence: 70%

Intrinsic dissipation mechanisms in metallic glass resonators

Meng

Nawano

Schroers

et al. 2019

The Journal of Chemical Physics

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Micro-and nano-resonators have important applications including sensing, navigation, and biochemical detection. Their performance is quantified using the quality factor Q, which gives the ratio of the energy stored to the energy dissipated per cycle. Metallic glasses are a promising materials class for micro-and nano-scale resonators since they are amorphous and can be fabricated precisely into complex shapes on these lengthscales. To understand the intrinsic dissipation mechanisms that ultimately limit large Q-values in metallic glasses, we perform molecular dynamics simulations to model metallic glass resonators subjected to bending vibrations. We calculate the vibrational density of states, redistribution of energy from the fundamental mode of vibration, and Q versus the kinetic energy per atom K of the excitation. In the linear and nonlinear response regimes where there are no atomic rearrangements, we find that Q → ∞ (since we do not consider coupling to the environment). We identify a characteristic Kr above which atomic rearrangements occur, and there is significant energy leakage from the fundamental mode to higher frequencies, causing finite Q. Thus, Kr is a critical parameter determining resonator performance. We show that Kr decreases as a power-law, Kr ∼ N −k , with increasing system size N , where k ≈ 1.3. We estimate the critical strain γr ∼ 10 −8 for micron-sized resonators below which atomic rearrangements do not occur, and thus large Q-values can be obtained when they are operated below γr. We find that Kr for amorphous resonators is comparable to that for resonators with crystalline order. arXiv:1907.00052v1 [cond-mat.mtrl-sci] 28 Jun 2019 AB = 1.5, σ AA = 1.0, σ BB = 0.88, and σ AB = 0.8. All atoms have the same mass m. The energy, length, and pressure scales are given in terms of AA , σ AA , and AA /σ 3 AA , respectively.

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Section: Methods To Increase Kr and Enhance Qmentioning

confidence: 70%

Intrinsic dissipation mechanisms in metallic glass resonators

Meng

Nawano

Schroers

et al. 2019

The Journal of Chemical Physics

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“…, where SR t is the characteristic time of structural relaxation [80]. In the author's opinion, the latter situation seems to be most likely.…”

Section: Sr T <mentioning

confidence: 85%

Mechanical Relaxations in Metallic Glasses

Khonik

2003

SSP

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The mechanical relaxation phenomena occurring in metallic glasses at temperatures above and below the room temperature are considered. It is argued that the response to applied stress is determined mainly by the rate of irreversible structural relaxation. This rate is maximal at temperatures T >T 0 » 400 K for samples in the initial state. In this temperature range, metallic glasses display typical viscoelastic behavior under low frequency and quasi-static loading. At low temperatures, T < T 0 , the rate of irreversible structural relaxation is small resulting in a change of deformation behavior to the localized elastic-plastic flow. Mechanical properties of metallic glasses in this case closely resemble those of crystalline metals being deformed via the dislocation mechanism.

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“…In most cases the heat treatment significantly affects the damping values. More data and details on damping mechanisms in different groups of metallic materials can be found in literature: group 1: [4,7,21,32]; group 2: [33][34][35][36][37]; group 3: [38][39][40]45]; group 4: [4,41,42]; group 5: [26][27][28]43,44], and also at this Symposium.…”

Section: Hidamets With Extremely High Hydrogen Concentrationmentioning

confidence: 99%