Universal secondary relaxation and unusual brittle-to-ductile transition in metallic glasses

Wang, Q.; Liu, J.J.; Ye, Y.F.; Liu, T.T.; Wang, S.; Liu, C.T.; J, Lu; Yang, Yong

doi:10.1016/j.mattod.2017.05.007

Cited by 124 publications

(66 citation statements)

References 55 publications

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“…The presence of the loss peak, referred to as γ‐relaxation, in all these different alloys suggests a general phenomenon of a fast relaxation mechanism at low temperatures, which is in agreement with subsequent studies . The activation energy of this process is of the order of 0.2–0.3 eV, which offsets it distinctly from α‐ and β‐relaxation that typically have higher activation barriers of several electron volts and 0.6–1.5 eV, respectively.…”

Section: Tuning Structure Homogeneously Via Thermal and Mechanical Prsupporting

confidence: 88%

“…Such characteristic barrier energies are in very good agreement with empirically derived β‐relaxation energies in other MGs, but much smaller than those reported for α‐relaxation and larger than for γ‐relaxation . The close correspondence of both relaxation times and energies suggests that the development of viscoelastic (structural) heterogeneities at the scale of a few nanometers is directly linked to sub‐ T g relaxation of the MG, which means that spatial mapping of nanoscale structural fluctuations now reveals direct insight into the process of macroscopic energy release during annealing.…”

Section: Experimentally Resolved Structural Length Scales In As‐prepasupporting

confidence: 82%

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Elastic Fluctuations and Structural Heterogeneities in Metallic Glasses

Liu

Maaß

2018

Adv Funct Materials

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Suppressing crystallization of a metallic melt results in a disordered solid, also known as a metallic glass. One may conclude that a metallic glass is free of defined structural length scales beyond some atomic-scale value that characterizes short-and medium-range order. While it is well known from atomistic modeling that a metallic glass is structurally heterogeneous, heterogeneities at such a small length scale can hardly be resolved in experiments. This review highlights experimental insights into elastic fluctuations and structural heterogeneities that emerge at scales between a few nanometers and tens to hundreds of micrometers. It distinguishes between structural and property fluctuations in as-cast metallic glasses, and heterogeneities introduced by elastic and inhomogeneous plastic deformation. As-cast glasses reveal elastic fluctuations across 3 orders of magnitude, suggesting a hierarchy of length scales that can be tuned by thermomechanical processing. Similarly, nanoscale strain localization into shear bands drives the formation of structural and elastic heterogeneities at both the nano-and the microscale. It is proposed that both types of fluctuations will allow one to quantitatively define structure-property relationships via measurable length scales-an approach that has largely contributed to the engineering success of crystalline metals.

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Section: Tuning Structure Homogeneously Via Thermal and Mechanical Prsupporting

confidence: 88%

Section: Experimentally Resolved Structural Length Scales In As‐prepasupporting

confidence: 82%

Elastic Fluctuations and Structural Heterogeneities in Metallic Glasses

Liu

Maaß

2018

Adv Funct Materials

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“…Largely because of their unique structural and thermodynamic peculiarities, the MGs have exhibited many advanced structural and functional properties since their discovery, such as high strength, superior elasticity, excellent corrosion resistance, stable wear resistance, unique soft magnetic properties, etc. However, due to their remaining mysterious intrinsic properties of atomic arrangement, structural dynamic heterogeneity, relaxation, and aging, their current large‐scale industrialized application has only been focused on manufacturing large‐transformer units (soft magnetic property) and a few structural components such as golf drivers (elasticity and strength). Therefore, developing new practical applications of MGs is an active and pivotal topic in materials science.…”

Section: Introductionmentioning

confidence: 99%

Attractive In Situ Self‐Reconstructed Hierarchical Gradient Structure of Metallic Glass for High Efficiency and Remarkable Stability in Catalytic Performance

Jia

Wang

Sun

et al. 2019

Adv Funct Materials

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Metallic glass (MG), with the superiorities of unique disordered atomic structure and intrinsic chemical heterogeneity, is a new promising and competitive member in the family of environmental catalysts. However, what is at stake for MG catalysts is that their high catalytic efficiency is always accompanied by low stability and the disordered atomic configurations, as well as the structural evolution, related to catalytic performance, which raises a primary obstacle for their widespread applications. Herein, a non-noble and multicomponent Fe 83 Si 2 B 11 P 3 C 1 MG catalyst that presents a fascinating catalytic efficiency while maintaining remarkable stability for wastewater remediation is developed. Results indicate that the excellent efficiency of the MG catalysts is ascribed to a unique atomic coordination that causes an electronic delocalization with an enhanced electron transfer. More importantly, the in situ selfreconstructed hierarchical gradient structure, which comprises a top porous sponge layer and a thin amorphous oxide interfacial layer encapsulating the MG surface, provides matrix protection together with high permeability and more active sites. This work uncovers a new strategy for designing high-performance non-noble metallic catalysts with respect to structural evolution and alteration of electronic properties, establishing a solid foundation in widespread catalytic applications.

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“…Experiments have shown that the relaxation happens in almost all the timescales which can be roughly separated into three types when it is close to glass transition temperature (Tg) [2,3]: (1) The primary one, named α-relaxation with the typical timescale >10 -3 s, is associated with structural relaxation and play the main role in glass transition; (2) the secondary relaxation with the timescale of 10 -8~1 0 -3 s, which is often called (slow) β relaxation, is related to localized atomic motion though a mechanism that is still vague; (3) and the third relaxation with the timescale of 10 -8~1 0 -12 s, usually called fast β relaxation, could be related to the rattling motion of caged particles [4]. At present, lots of efforts have been devoted to the understanding of β relaxation [3,[5][6][7][8][9][10][11][12] because it helps disclose the nature of glass transition [10] and adjust the properties of glass [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

On the mechanical β relaxation in glass and its relation to the double-peak phenomenon in impulse excited vibration at high temperatures

Wang

Ruan

2020

Journal of Non-Crystalline Solids

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A viscoelastic model is established to reveal the relation between α-β relaxation of glass and the double-peak phenomenon in the experiments of impulse excited vibration. In the modelling, the normal mode analysis (NMA) of potential energy landscape (PEL) picture is employed to describe mechanical α and β relaxations in a glassy material. The model indicates that a small β relaxation can lead to an apparent double-peak phenomenon resulted from the free vibration of a glass beam when the frequency of β relaxation peak is close to the natural frequency of specimen. The theoretical prediction is validated by the acoustic spectrum of a fluorosilicate glass beam excited by a mid-span impulse. Furthermore, the experimental results indicate a negative temperature-dependence of the frequency of β relaxation in the fluorosilicate glass S-FSL5 which can be explained based on the physical picture of fragmented oxide-network patches in liquid-like regions.

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Universal secondary relaxation and unusual brittle-to-ductile transition in metallic glasses

Cited by 124 publications

References 55 publications

Elastic Fluctuations and Structural Heterogeneities in Metallic Glasses

Elastic Fluctuations and Structural Heterogeneities in Metallic Glasses

Attractive In Situ Self‐Reconstructed Hierarchical Gradient Structure of Metallic Glass for High Efficiency and Remarkable Stability in Catalytic Performance

On the mechanical β relaxation in glass and its relation to the double-peak phenomenon in impulse excited vibration at high temperatures

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