Cooling-rate dependence of the density of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Pd</mml:mi></mml:mrow><mml:mrow><mml:mn>40</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ni</mml:mi></mml:mrow><mml:mrow><mml:mn>10</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>30</mml:mn>

Hu, Xiaoping; Ng, S. C.; Feng, Yuan Ping; Li, Y.

doi:10.1103/physrevb.64.172201

Cited by 51 publications

(28 citation statements)

References 18 publications

(11 reference statements)

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“…Structural analysis reveals no crystallization: all voxels return to an amorphous, vitrified state, although the rapid quenching reduces the amount of short-range icosahedral order initially present [28]. The properties of metallic glasses depend upon the quench rate used during their synthesis [45][46][47]. Thus, we investigate whether the properties of the rapidly quenched material in TSs match those of equilibrium liquids quenched at the same rate.…”

Section: Sqzsmentioning

confidence: 88%

Radiation response of amorphous metal alloys: Subcascades, thermal spikes and super-quenched zones

Baumer

Demkowicz

2015

Acta Materialia

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Section: Sqzsmentioning

confidence: 88%

Radiation response of amorphous metal alloys: Subcascades, thermal spikes and super-quenched zones

Baumer

Demkowicz

2015

Acta Materialia

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“…In the classical picture, nucleation is considered to take place in a solution of ions that has become supersaturated, leading to the nucleation of the solid phase by stochastic solute clustering, and the earliest crystal precursor is considered to be a cluster of critical size (14,15). Because of the stochastic formation mechanism, such metastable clusters are a rare species.…”

Section: Stable Prenucleation Calcium Carbonate Clustersmentioning

confidence: 99%

“…This has been the basis for recent theoretical studies (12,13) of structural models of metallic glasses, in which a correlation between compositions having especially dense packing and compositions that are known to quench to the glassy state at relatively low cooling rates was sought, but not obtained. Earlier studies of the density of glasses, based on the Archimedes method, have been mostly limited to relatively narrow compositional ranges of ternary and quaternary alloys with large critical sample sizes for glass formation (14)(15)(16), and no correlation between density and the ease of glass formation has been demonstrated.…”

mentioning

confidence: 99%

Matching Glass-Forming Ability with the Density of the Amorphous Phase

Guo

Kalb

et al. 2008

Science

Self Cite

332

199

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The density of the amorphous phase of metals is generally thought to be related to glass formation, but this correlation has not been demonstrated experimentally to date. In this work, systematic deflection measurements using microcantilevers and a combinatorial deposition method show a correlation between glass-forming ability and the density change upon crystallization over a broad compositional range in the copper-zirconium binary system. Distinct peaks in the density of the amorphous phase were found to correlate with specific maxima in the critical thickness for glass formation. Our findings provide quantitative data for the development of structural models of liquids that are readily quenched to the amorphous state. The experimental method developed in this work can facilitate the search for new glass-forming alloys. Metallic glasses are amorphous metals that do not have a structure with longrange atomic order like crystalline materials do, but have pronounced short-and medium-range order at the atomic scale. Because of their very different properties as compared to those of their crystalline counterparts, metallic glasses are very promising materials for future structural, chemical, and magnetic applications (1, 2). The packing density of the amorphous phase is a key consideration in studying the formation of metallic glasses (2-5). A liquid of high packing density (6-8) has a low free volume content and a correspondingly low atomic mobility (9-11). Upon quenching, such a liquid is expected to have a strong kinetic constraint on nucleation and the subsequent growth of crystals. This has been the basis for recent theoretical studies (12, 13) of structural models of metallic glasses, in which a correlation between compositions having especially dense packing and compositions that are known to quench to the glassy state at relatively low cooling rates was sought, but not obtained. Earlier studies of the density of glasses, based on the Archimedes method, have been mostly limited to relatively narrow compositional ranges of ternary and quaternary alloys with large critical sample sizes for glass formation (14-16), and no correlation between density and the ease of glass formation has been demonstrated.We have developed a method for the measurement of density changes, using microfabricated Si-rich silicon nitride (SiN) cantilevers (17). Owing to the small size and close spacing of the cantilevers, the deposition of alloy films with compositions that varied in a controlled way from cantilever to cantilever allowed a combinatorial approach to measurements of density changes for a broad range of compositions, with high compositional resolution. This process is schematically illustrated in fig. S1. Heatinginduced crystallization of the initially amorphous Cu-Zr films causes an increase in density (a decrease in volume) that causes an upward deflection of the cantilevers, as a result of the tensile elastic mismatch strain developed at the interface between the film and the cantilever. By measuring the magnitude of ...

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“…As discussed in literature, glass formation ability (GFA) of BMGs is best described by the critical cooling rate, R c [1-3]. In addition to its role as one of the decisive factors in the vitrification process of BMGs, the cooling rate also influences the final microstructure [4,5] and physical properties [6]. Both theoretic and experimental results have directly shown that mechanical properties of BMGs were closely related to cooling rates applied during the sample preparation process [7,8].…”

mentioning

confidence: 97%

Effects of cooling rates on the mechanical properties of a Ti-based bulk metallic glass

Xiao

Liu

et al. 2010

Sci. China Phys. Mech. Astron.

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Mechanical properties of the glassy specimens fabricated at different cooling rates with a composition of Ti 40 Zr 25 Cu 12 Ni 3 Be 20 were systematically investigated. It was confirmed that faster cooling rates caused not only a larger amount of frozen-in free volume but also a higher glass transition temperature in the bulk glassy alloy. Increase in the free volume was found to favor plastic deformation and then to give rise to larger compressive plasticity, whilst the rise in the glass transition temperature seemed to be closely related to the higher yield strength. Moreover, the increase of yield strength and plasticity induced by fast cooling rates may also be associated with the residual stress generated during the fabrication process. Our results suggest that the deformation behavior of bulk metallic glasses is sensitive to various factors and influences from the other factors should be excluded as far as cooling-rate effects on bulk metallic glasses are considered. bulk metallic glasses, mechanical properties, cooling-rate effects, residual stress PACS: 61.43.Dq, 65.60.+a, 81.05.KfBulk metallic glasses (BMGs) are usually fabricated by rapid-quenching techniques in which the cooling rate is a key processing factor. As discussed in literature, glass formation ability (GFA) of BMGs is best described by the critical cooling rate, R c [1-3]. In addition to its role as one of the decisive factors in the vitrification process of BMGs, the cooling rate also influences the final microstructure [4,5] and physical properties [6]. Both theoretic and experimental results have directly shown that mechanical properties of BMGs were closely related to cooling rates applied during the sample preparation process [7,8]. An increase in the cooling rate is likely to give rise to a larger plasticity and lower yield strength [9]. However, further investigations are needed for a full understanding of the cooling-rate effects on mechanical properties of BMGs.Recently, the deformation behavior of amorphous solids was found extremely sensitive to the other factors such as Poison's ratio [10], residual stress [11], and testing specimen sizes [12,13]. As such, effects of the cooling rate are often overlapped with these factors in BMGs. It is thus necessary to exclude influences from the other factors in terms of the cooling-rate effects. In this paper, we attempt to investigate the cooling-rate dependence of mechanical properties in BMGs and the related mechanisms via carefully designed experiments. ExperimentMaster alloys with nominal compositions of Ti 40 Zr 25 -Cu 12 Ni 3 Be 20 (at.%) [14] were prepared by arc-melting a mixture of raw metals including 99.999% Ti, 99.5% Zr, 99.99%Cu, 99.99%Ni and 99.99% Be in a Ti-gettered argon atmosphere. The alloy ingots were melted six times to ensure a compositional homogeneity. Rod-shaped samples were obtained by suction-casting the molten alloys into copper molds with diameters of 2, 5, 8 and 10 mm in helium atmosphere. The amorphous structure of the as-cast samples

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Cooling-rate dependence of the density ofPd40Ni10Cu30

Cited by 51 publications

References 18 publications

Radiation response of amorphous metal alloys: Subcascades, thermal spikes and super-quenched zones

Radiation response of amorphous metal alloys: Subcascades, thermal spikes and super-quenched zones

Matching Glass-Forming Ability with the Density of the Amorphous Phase

Effects of cooling rates on the mechanical properties of a Ti-based bulk metallic glass

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