Calculation of some metallic-glass properties, based on the use of a Gaussian distribution for the nearest-neighbour distance III. Elastic constants

Using the full-potential linear muffin-tin orbital method within the local spin-density approximation we analyse the influence of the nearest neighbour distance on fcc(111) or hcp(0001) iron layers. The LDA-LSDA error in describing ferromagnetic phases is determined to be at least 15 mRy/atom. As a consequence of this error, our calculations favour paramagnetic ground states. In this sense, the reported results have some model character. However, our analysis of the elastic energy cost under distortions should hold for transition metals in general. Allowing relaxations of the interplanar distance the fcc phase can become energetically favourable over the hcp phase at large lattice mismatches. The main reason for this behaviour is the enhanced stiffness of the hcp interplanar bonds due to the shortening of the axial c/a ratio.

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Flow units perspective on sensitivity and reliability of metallic glass properties

Intermetallics ◽

10.1016/j.intermet.2015.10.024 ◽

2016 ◽

Vol 69 ◽

pp. 98-102 ◽

Cited By ~ 6

Author(s):

A. Gulzar ◽

Z.G. Zhu ◽

K. Shahzad ◽

D.Q. Zhao ◽

W.H. Wang

Keyword(s):

Metallic Glass ◽

Flow Units ◽

Glass Properties

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Simulation of Dynamics of Solid-Liquid Transition

MRS Proceedings ◽

10.1557/proc-407-245 ◽

1995 ◽

Vol 407 ◽

Cited By ~ 1

Author(s):

Y. Kogure ◽

H. Masuyama ◽

M. Doyama

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulations ◽

Nearest Neighbour ◽

Neighbour Distance ◽

Liquid Transition ◽

Dynamics Simulations ◽

Solid Liquid ◽

Copper Crystals

ABSTRACTMolecular dynamics simulations on the solid-liquid transition of copper crystals have been performed. The configulation and the motion of atoms are monitored by RDF. It is seen that the height of the first peak in the RDF, which located at the nearest neighbour distance, decreased drastically as the temperature is increased.

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Struktur von Schmelzen aus dem System Wismut-Antimon mittels Neutronenbeugung

Zeitschrift für Naturforschung A ◽

10.1515/zna-1976-0114 ◽

1976 ◽

Vol 31 (1) ◽

pp. 90-101 ◽

Cited By ~ 17

Author(s):

Peter Lamparter ◽

Siegfried Steeb ◽

Walter Knoll

Keyword(s):

Neutron Diffraction ◽

Coordination Number ◽

Covalent Binding ◽

The Other ◽

Nearest Neighbour ◽

Neighbour Distance ◽

The Mean ◽

The One ◽

Subsidiary Maxima ◽

Versus Concentration

Neutron diffraction work (λ = 0.695 Å) was done with molten Bi-Sb-alloys in the temperature range between 550 and 750 °C. Furthermore molten Bi was investigated at 300 °C. The interference functions show subsidiary maxima especially for alloys with higher Sb-concentrations. Evaluation yields, that the melts contain two different kinds of structure:a) The one kind shows coordination number 9 and a statistical distribution of the atoms of two components. This kind is more inetal-like.b) The other kind shows coordination number 3, consists of non-centered tetrahedra with smaller nearest neighbour distance. It shows covalent binding.In molten Sb the nearest neighbour distance amounts up to 3.16 - 3.19 Å for theo ne kind and up to 2.64 -2.78 Å fort he other kind, which yields an mean distance of 2.99 Å, which was observed. The dependence of the concentration of the statistical kind of meld, of the (Sb)4-, and the (Bi)4-kind from the concentration of the whole melt is given.By the model described the run of the measured mean coordination number and the mean distance versus concentration can be well explained.

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Comparison of Certain Local Pseudopotentials and a New Proposal

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.665.70 ◽

2013 ◽

Vol 665 ◽

pp. 70-73

Author(s):

Smruti J. Patel ◽

A.Y. Vahora ◽

B.Y. Thakore ◽

Ashvin R. Jani

Keyword(s):

Phonon Dispersion ◽

Liquid Metals ◽

Form Factors ◽

Model Potential ◽

Test Case ◽

Nearest Neighbour ◽

Core Radius ◽

Phonon Dispersion Curves ◽

Neighbour Distance

A new proposal of a local pseudopotential is put forwarded here depending on the concept of extended core radius in which half of the nearest neighbour distance is treated as effective core radius. There is no input of any property for fitting this parameter in this formalism. This pseudopotential is found to satisfy all the necessary requirements for applications. With this model potential we have evaluated the form factors for several bcc, fcc and hcp metals and achieved excellent agreement with previous results. On the same footing, we have examined other 14 local pseudo potentials also and on the basis of the comparison, the presently proposed pseudopotential is found to be much better. As a test case study, we have evaluated phonon dispersion curves of some liquid metals, viz. Na (Z = 1), Mg (Z = 2), Al (Z= 3) and Pb (Z = 4) and obtained quite satisfactory results.

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Dominating lengthscales of zebrafish collective behaviour

PLoS Computational Biology ◽

10.1371/journal.pcbi.1009394 ◽

2022 ◽

Vol 18 (1) ◽

pp. e1009394

Author(s):

Yushi Yang ◽

Francesco Turci ◽

Erika Kague ◽

Chrissy L. Hammond ◽

John Russo ◽

...

Keyword(s):

Collective Motion ◽

Persistence Length ◽

Three Dimensional ◽

Temporal Correlation ◽

Model System ◽

Collective Behaviour ◽

Living Systems ◽

Nearest Neighbour ◽

Length Scales ◽

Neighbour Distance

Collective behaviour in living systems is observed across many scales, from bacteria to insects, to fish shoals. Zebrafish have emerged as a model system amenable to laboratory study. Here we report a three-dimensional study of the collective dynamics of fifty zebrafish. We observed the emergence of collective behaviour changing between ordered to randomised, upon adaptation to new environmental conditions. We quantify the spatial and temporal correlation functions of the fish and identify two length scales, the persistence length and the nearest neighbour distance, that capture the essence of the behavioural changes. The ratio of the two length scales correlates robustly with the polarisation of collective motion that we explain with a reductionist model of self–propelled particles with alignment interactions.

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Universal structural parameter to quantitatively predict metallic glass properties

Nature Communications ◽

10.1038/ncomms13733 ◽

2016 ◽

Vol 7 (1) ◽

Cited By ~ 59

Author(s):

Jun Ding ◽

Yong-Qiang Cheng ◽

Howard Sheng ◽

Mark Asta ◽

Robert O. Ritchie ◽

...

Keyword(s):

Metallic Glass ◽

Structural Parameter ◽

Glass Properties

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Pressure Dependence of Elastic Constants and Debye Temperature for Zr50.5Ti4.8Cu19.0Ni11.4Al14.3 Bulk Metallic Glass

Journal of Materials Research ◽

10.1557/jmr.2002.0264 ◽

2002 ◽

Vol 17 (7) ◽

pp. 1785-1788 ◽

Cited By ~ 5

Author(s):

Ping Wen ◽

Ru Ju Wang ◽

Wei Hua Wang

Keyword(s):

Metallic Glass ◽

Bulk Metallic Glass ◽

Elastic Constants ◽

Pressure Dependence ◽

High Resolution Electron Microscopy ◽

Resolution Electron ◽

Homogeneous Composition ◽

Overlap Method ◽

Pulse Echo ◽

Isothermal Equation

The microstructure of Zr50.5Ti4.8Cu19.0Ni11.4Al14.3 bulk metallic glass (BMG) was investigated by high-resolution electron microscopy. The microstructure of the BMG is of homogeneous composition and short-range ordered microstructure. Using an ultrasonic technique with the pulse echo overlap method, the pressure-dependent acoustic velocities of the BMG have been measured up to 0.5 GPa. The elastic constants and their pressure dependence have been obtained. The isothermal equation of state (EOS) of the BMG is determined in terms of the Murnaghan form. With the results of the elastic constants and the EOS for those of its metallic components, the atomic configuration of the BMG is discussed.

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