General 2.5 power law of metallic glasses

Metallic glass (MG) is an important new category of materials, but very few rigorous laws are currently known for defining its “disordered” structure. Recently we found that under compression, the volume (V) of an MG changes precisely to the 2.5 power of its principal diffraction peak position (1/q1). In the present study, we find that this 2.5 power law holds even through the first-order polyamorphic transition of a Ce68Al10Cu20Co2 MG. This transition is, in effect, the equivalent of a continuous “composition” change of 4f-localized “big Ce” to 4f-itinerant “small Ce,” indicating the 2.5 power law is general for tuning with composition. The exactness and universality imply that the 2.5 power law may be a general rule defining the structure of MGs.

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Heating Rate and Composition Dependence of Crystallization Temperature of Cu-Based Metallic Glasses

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1141.156 ◽

2016 ◽

Vol 1141 ◽

pp. 156-161 ◽

Cited By ~ 1

Author(s):

Supriya Kasyap ◽

Sonal Prajapati ◽

Arun Pratap

Keyword(s):

Metallic Glass ◽

Heating Rate ◽

Power Law ◽

Metallic Glasses ◽

Crystallization Temperature ◽

Composition Dependence ◽

Theoretical Expression ◽

Linear Variation ◽

Peak Crystallization Temperature ◽

Good Agreement

The variation of onset of crystallization temperature (Tx) and peak crystallization temperature (Tp) with heating rate (q) is studied. Tx and Tp vary in a power law behavior with heating rate (q) for Cu60 Zr20Ti20 metallic glass and these parameters show a linear variation for Cu60Zr40 metallic glass. The power law variation is expressed as Tx (or Tp) = T0 [q]y; where, q is the normalized heating rate, T0 is the Tx (or Tp) at a heating rate of 10Cmin-1. Further, the calculated values of Tx (or Tp) are found to be in good agreement with the experimental results. Hence, the power law relation is found to be an appropriate theoretical expression for the variation of crystallization temperature (Tx or Tp) with heating rate (q) for Cu60 Zr20Ti20 metallic glass. In addition to heating rate, the composition of a metallic glass also affects its crystallization temperature. It is observed that the characteristics temperatures shift towards higher values with increase in number of components.

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Pd-Based Metallic Glass Films Formed by Electrodeposition Process

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.194.183 ◽

2012 ◽

Vol 194 ◽

pp. 183-186 ◽

Cited By ~ 2

Author(s):

Chihiro Mochizuki ◽

Takashi Senga ◽

Masami Shibata

Keyword(s):

Metallic Glass ◽

Diffraction Pattern ◽

Metallic Glasses ◽

Amorphous Structure ◽

Diffraction Peak ◽

Metallic Alloys ◽

X Ray Diffraction ◽

Electrodeposition Process ◽

X Ray ◽

Glass Films

The formation of Pd-Ni-P and Pd-Ni-Cu-P metallic glass films using the electrodeposition method was examined. In this study, the structure and composition of these metallic alloys were investigated at various condition of electrodeposition. The X-ray diffraction pattern on the electrodeposited Pd-Ni-P films in the range of 18-69 at% Pd, 12-62 at% Ni and 9-21 at% P showed a broad diffraction peak, which indicates metallic amorphous structure. A result of DSC showed that the electrodeposited Pd-Ni-P films in the range of 36-57 at% Pd, 24-47 at% Ni and 16-21 at% P were metallic glasses. In addition, it was proven that the electrodeposited Pd54Cu8Ni22P16 film was metallic glass.

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Tension-Tension Fatigue Behavior of High-Toughness Zr61Ti2Cu25Al12 Bulk Metallic Glass

Materials ◽

10.3390/ma14112815 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2815

Author(s):

Yu Hang Yang ◽

Jun Yi ◽

Na Yang ◽

Wen Liang ◽

Hao Ran Huang ◽

...

Keyword(s):

Fracture Toughness ◽

Shear Band ◽

Metallic Glass ◽

Bulk Metallic Glass ◽

Fatigue Resistance ◽

Metallic Glasses ◽

Stress Amplitude ◽

Fatigue Behavior ◽

Bulk Metallic Glasses ◽

High Toughness

Bulk metallic glasses have application potential in engineering structures due to their exceptional strength and fracture toughness. Their fatigue resistance is very important for the application as well. We report the tension-tension fatigue damage behavior of a Zr61Ti2Cu25Al12 bulk metallic glass, which has the highest fracture toughness among BMGs. The Zr61Ti2Cu25Al12 glass exhibits a tension-tension fatigue endurance limit of 195 MPa, which is higher than that of high-toughness steels. The fracture morphology of the specimens depends on the applied stress amplitude. We found flocks of shear bands, which were perpendicular to the loading direction, on the surface of the fatigue test specimens with stress amplitude higher than the fatigue limit of the glass. The fatigue cracking of the glass initiated from a shear band in a shear band flock. Our work demonstrated that the Zr61Ti2Cu25Al12 glass is a competitive structural material and shed light on improving the fatigue resistance of bulk metallic glasses.

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Synthesis of Bulk Zr48Cu36Al8Ag8 Metallic Glass by Hot Pressing of Amorphous Powders

Journal of Manufacturing and Materials Processing ◽

10.3390/jmmp5010023 ◽

2021 ◽

Vol 5 (1) ◽

pp. 23

Author(s):

Tianbing He ◽

Nevaf Ciftci ◽

Volker Uhlenwinkel ◽

Sergio Scudino

Keyword(s):

Metallic Glass ◽

Metallic Glasses ◽

Flow Behavior ◽

Matrix Composites ◽

Powder Consolidation ◽

Low Viscosity ◽

Flash Annealing ◽

Amorphous Powders ◽

Temperature Window ◽

Glass Matrix Composites

The critical cooling rate necessary for glass formation via melt solidification poses inherent constraints on sample size using conventional casting techniques. This drawback can be overcome by pressure-assisted sintering of metallic glass powders at temperatures above the glass transition, where the material shows viscous-flow behavior. Partial crystallization during sintering usually exacerbates the inherent brittleness of metallic glasses and thus needs to be avoided. In order to achieve high density of the bulk specimens while avoiding (or minimizing) crystallization, the optimal combination between low viscosity and long incubation time for crystallization must be identified. Here, by carefully selecting the time–temperature window for powder consolidation, we synthesized highly dense Zr48Cu36Ag8Al8 bulk metallic glass (BMG) with mechanical properties comparable with its cast counterpart. The larger ZrCu-based BMG specimens fabricated in this work could then be post-processed by flash-annealing, offering the possibility to fabricate monolithic metallic glasses and glass–matrix composites with enhanced room-temperature plastic deformation.

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Basic Research on Precision and Micro Machining of Metallic Glasses. Deformation Behavior of Zr Based Bulk Metallic Glass under Tensile Stress.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C ◽

10.1299/kikaic.67.2707 ◽

2001 ◽

Vol 67 (660) ◽

pp. 2707-2712 ◽

Cited By ~ 1

Author(s):

Seiichi HATA ◽

Yongdong LIU ◽

Yasuyuki NAGAMINE ◽

Akira SHIMOKOHBE

Keyword(s):

Metallic Glass ◽

Tensile Stress ◽

Bulk Metallic Glass ◽

Metallic Glasses ◽

Deformation Behavior ◽

Basic Research ◽

Micro Machining

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Examination of Particle Tails

Journal of Artificial Evolution and Applications ◽

10.1155/2008/893237 ◽

2008 ◽

Vol 2008 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Tim Blackwell ◽

Dan Bratton

Keyword(s):

Power Law ◽

Difference Equations ◽

Particle Swarm ◽

Second Order ◽

Particle Swarm Optimisation ◽

Position Distribution ◽

Length Scales ◽

Stochastic Difference Equations ◽

First Order ◽

Second Order Equations

The tail of the particle swarm optimisation (PSO) position distribution at stagnation is shown to be describable by a power law. This tail fattening is attributed to particle bursting on all length scales. The origin of the power law is concluded to lie in multiplicative randomness, previously encountered in the study of first-order stochastic difference equations, and generalised here to second-order equations. It is argued that recombinant PSO, a competitive PSO variant without multiplicative randomness, does not experience tail fattening at stagnation.

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ON SOME NEW SOLUTIONS OF THE MULTI-DIMENSIONAL FIRST ORDER PARTIAL DIFFERENTIAL EQUATION WITH POWER-LAW NON-LINEARITIES

Vestnik Tomskogo gosudarstvennogo universiteta Matematika i mekhanika ◽

10.17223/19988621/35/3 ◽

2015 ◽

pp. 18-25

Author(s):

Igor Vladimirovich RAKHMELEVICH ◽

Keyword(s):

Differential Equation ◽

Partial Differential Equation ◽

Power Law ◽

Order Partial Differential Equation ◽

Partial Differential ◽

First Order

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Atomic-scale viscoplasticity mechanisms revealed in high ductility metallic glass films

Scientific Reports ◽

10.1038/s41598-019-49910-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Hosni Idrissi ◽

Matteo Ghidelli ◽

Armand Béché ◽

Stuart Turner ◽

Sébastien Gravier ◽

...

Keyword(s):

Metallic Glass ◽

Metallic Glasses ◽

Shear Banding ◽

Atomic Scale ◽

Microscopy Imaging ◽

Rate Dependent ◽

Imaging And Spectroscopy ◽

Shear Transformation Zones ◽

The Impact ◽

Glass Films

Abstract The fundamental plasticity mechanisms in thin freestanding Zr65Ni35 metallic glass films are investigated in order to unravel the origin of an outstanding strength/ductility balance. The deformation process is homogenous until fracture with no evidence of catastrophic shear banding. The creep/relaxation behaviour of the films was characterized by on-chip tensile testing, revealing an activation volume in the range 100–200 Å3. Advanced high-resolution transmission electron microscopy imaging and spectroscopy exhibit a very fine glassy nanostructure with well-defined dense Ni-rich clusters embedded in Zr-rich clusters of lower atomic density and a ~2–3 nm characteristic length scale. Nanobeam electron diffraction analysis reveals that the accumulation of plastic deformation at room-temperature correlates with monotonously increasing disruption of the local atomic order. These results provide experimental evidences of the dynamics of shear transformation zones activation in metallic glasses. The impact of the nanoscale structural heterogeneities on the mechanical properties including the rate dependent behaviour is discussed, shedding new light on the governing plasticity mechanisms in metallic glasses with initially heterogeneous atomic arrangement.

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