The excess wing of bulk metallic glass forming liquids

Wang, Wei Hua; Wen, Ping; Liu, Xiaofeng

doi:10.1016/j.jnoncrysol.2006.01.149

Cited by 19 publications

(8 citation statements)

References 30 publications

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“…The phenomenon shown in Fig. is similar to the results of temperature scan with DMA for realistic glassy materials . This indicates that the simple two‐level model can be used to fit experimental results.…”

Section: Numerical Resultssupporting

confidence: 77%

Modeling of Random Relaxation Paths of Amorphous Material

Ruan

Zhang

2013

J. Am. Ceram. Soc.

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This study aims to understand the viscosity variation of amorphous materials, and hence establish a theoretical model for reliable applications. The investigation was carried out by simplifying an amorphous system to a mixture of many subsystems which switch their energy states and relaxation processes stochastically. The response of the macroscopic system is then treated as an ensemble average of relaxations of individual subsystems. Our derivation illuminates the transition from exponential to nonexponential relaxation and that the sudden increase of fragility in the viscosity-temperature relation with reducing temperature could be attributed to the bifurcation from the harmonic mean of the subsystems towards the arithmetic mean. The successful application of our model to the amorphous selenium indicates that the model captures the fundamental mechanism of viscosity variation.

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Section: Numerical Resultssupporting

confidence: 77%

Modeling of Random Relaxation Paths of Amorphous Material

Ruan

Zhang

2013

J. Am. Ceram. Soc.

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“…Concerning the shape of the relaxation function, Liu and Wang [97,98] fitted the DMA behavior of Ce-based and Zr-Ti-Cu-Ni-Be glasses assuming that τ(T) follows a VFT behavior and relaxation can be described by the KWW function. The loss modulus was computed by Fourier transform finding that in the temperature region higher than Tg the experimental data was well reproduced; however, in the lower temperature region, the fitting was poorer.…”

Section: Modeling Of the Mechanical Relaxation Spectrummentioning

confidence: 99%

Mechanical Relaxation of Metallic Glasses: An Overview of Experimental Data and Theoretical Models

Liu

Pineda

Crespo

2015

Metals

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Relaxation phenomena in glasses are a subject of utmost interest, as they are deeply connected with their structure and dynamics. From a theoretical point of view, mechanical relaxation allows one to get insight into the different atomic-scale processes taking place in the glassy state. Focusing on their possible applications, relaxation behavior influences the mechanical properties of metallic glasses. This paper reviews the present knowledge on mechanical relaxation of metallic glasses. The features of primary and secondary relaxations are reviewed. Experimental data in the time and frequency domain is presented, as well as the different models used to describe the measured relaxation spectra. Extended attention is paid to dynamic mechanical analysis, as it is the most important technique allowing one to access the mechanical relaxation behavior. Finally, the relevance of the relaxation behavior in the mechanical properties of metallic glasses is discussed.

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“…That is to say, for type A, the JG peak is so close to the primary peak or with so low amplitude, that only its high-frequency tail remain visible and the other part is hidden by the α peak, resulting in the phenomenon called the excess wing observed. The reason why the α and the JG peaks cannot decouple has been suggested by both experimental and simulational observation [102,103]. In a general way, the stronger glass formers have smaller microregions responsible for the α relaxation and consequently have stronger influence on the JG motions involved in certain size of cages.…”

Section: The Excess Wing and The Boson Peakmentioning

confidence: 97%

A new threshold of uncovering the nature of glass transition: The slow ß relaxation in glassy states

Zhang

Yue

et al. 2010

Chin. Sci. Bull.

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The glass transition involves more than one dynamic relaxation mechanisms in supercooled liquids, such as α relaxation, slow β relaxation and fast β relaxation and so on. For the traditional theoretical system, α relaxation is believed mainly responsible for the nature of the glass transition as the beginning of the phenomenon. This idea, however, has been open to a big challenge since recent studies have indicated that slow β relaxation closely relates to α relaxation. Slow β relaxation determines the characteristics of α relaxation and is the precursor and the more microscopic base of glass transition behavior. In order to illuminate the significance of slow β relaxation in the fields of the glass transition and the structure of supercooled liquids, the accomplished progress is summarized from different aspects such as on the correlation between α relaxation and slow β relaxation, on the manner of α-slow β relaxation merging, on the energy landscape, on the excess wing and on the thermodynamically phenomenological models. The tendency of investigation in slow β relaxation is also evaluated. glass transition, β relaxation, liquid fragility, energy landscape, excess wing, boson peak Citation: Hu L N, Zhang C Z, Yue Y Z, et al. A new threshold of uncovering the nature of glass transition: The slow β relaxation in glassy states.The nature of glass transition is one of the most focal and difficult points in the field of condensed matter physics, because the glass transition of complicated dynamic heterogeneity involves a dramatic slowing down of the structural relaxation, which ultimately brings the supercooled liquid into the glassy state. Correspondingly, the relaxation dynamics of supercooled liquids evolves with time from atomic vibrations, motion of cages, the β (secondary) relaxation, to finally the onset of fully cooperative α (primary) relaxation process [1]. In different methods of measurements, the relaxations with different mechanisms generally have different performance. Figure 1 gives the schematic view of the frequency-dependent dielectric loss in nonconducting glass-forming materials at constant temperatures. It is seen that the α relaxation peak at the lowest region of frequency is followed by another peak at a relatively high frequency range, which is attributed to the β relaxation. According to the classic theory of glass transition, the cooperative α relaxation which occurs in the long or medium range is believed mainly responsible for the glass transition phenomenon, whereas the β relaxations that occur at shorter times or higher frequencies play no important role; the α relaxation is the base of the glass transition. Based on this idea, a lot of theories (mainly from aspects of free volume [2] and the configurational entropy [3]) have been proposed, resulting in a general classical physicochemical picture of dynamic structural relaxation and thermodynamic glass transition. This idea, however, has been open to a big challenge since β relaxations, especially Johari-Goldstein type in rigid molecule...

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The excess wing of bulk metallic glass forming liquids

Cited by 19 publications

References 30 publications

Modeling of Random Relaxation Paths of Amorphous Material

Modeling of Random Relaxation Paths of Amorphous Material

Mechanical Relaxation of Metallic Glasses: An Overview of Experimental Data and Theoretical Models

A new threshold of uncovering the nature of glass transition: The slow ß relaxation in glassy states

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