Bubble Raft Model for an Amorphous Alloy

Simpson, A. W.; Hodkinson, Pauline H.

doi:10.1038/237320a0

Cited by 42 publications

(15 citation statements)

References 11 publications

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“…Bubble rafts can be made easily and inexpensively, equilibrate quickly, exhibit topological defects such as disclinations, dislocations and grain boundaries, and provide vivid images of the structure of defects. Bubble raft models have been used to study two-dimensional polycrystalline and amorphous arrays [148], nanoindentation of an initially defect-free crystal [149], and the dynamic behavior of crystals under shear [150]. In this section we review the experimental realization of a bubble-raft model for a paraboloidal crystal done by Bowick et al [136] by assembling a single layer of millimeter-sized soap bubbles on the surface of a rotating liquid, thus extending the classic work of Bragg and Nye on planar soap bubble rafts.…”

Section: Experimental Realization Of Paraboloidal Crystalsmentioning

confidence: 99%

Two-dimensional matter: order, curvature and defects

Bowick

Giomi

2009

Advances in Physics

340

458

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Many systems in nature and the synthetic world involve ordered arrangements of units on two-dimensional surfaces. We review here the fundamental role payed by both the topology of the underlying surface and its Gaussian curvature. Topology dictates certain broad features of the defect structure of the ground state but curvature-driven energetics controls the detailed structured of ordered phases. Among the surprises are the appearance in the ground state of structures that would normally be thermal excitations and thus prohibited at zero temperature. Examples include excess dislocations in the form of grain boundary scars for spherical crystals above a minimal system size, dislocation unbinding for toroidal hexatics, interstitial fractionalization in spherical crystals and the appearance of well-separated disclinations for toroidal crystals. Much of the analysis leads to universal predictions that do not depend on the details of the microscopic interactions that lead to order in the first place. These predictions are subject to test by the many experimental soft and hard matter systems that lead to curved ordered structures such as colloidal particles self-assembling on droplets of one liquid in a second liquid. The defects themselves may be functionalized to create ligands with directional bonding. Thus nano to meso scale superatoms may be designed with specific valency for use in building supermolecules and novel bulk materials. Parameters such as particle number, geometrical aspect ratios and anisotropy of elastic moduli permit the tuning of the precise architecture of the superatoms and associated supermolecules. Thus the field has tremendous potential from both a fundamental and materials science/supramolecular chemistry viewpoint. Contents

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Section: Experimental Realization Of Paraboloidal Crystalsmentioning

confidence: 99%

Two-dimensional matter: order, curvature and defects

Bowick

Giomi

2009

Advances in Physics

340

458

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“…For instance, the second criterion originates from a series of early studies conducted firstly by Mader et al [4] who argued that a critical radius mismatch of atoms nearly 15 % fits the experimental results on the formation of amorphous phase. Simpson and Hodkinson [5] also derived the same value by simulating the formation with rafts of soap bubbles. Subsequently, Egami and Waseda [6] and Egami and Aur [7] developed this kinds of concept with a view of geometric structure of amorphous phase.…”

Section: Introductionmentioning

confidence: 84%

Computer-Aided Development of Multicomponent Metallic Glasses

Takeuchi

Inoue

2002

MRS Proc.

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A synthesized calculation model for developing metallic glasses has been created by taking into account criteria for the achievement of high glass-forming ability (GFA) and viscosity. The model deals with amorphous-forming composition region (AFCR), crystallization temperature (T x ) and three GFA factors: critical cooling rate (R c ), reduced glass-transition temperature (T g /T m ) and supercooled liquid region (∆T x =T x -T g ) where T g and T m are glass transition and melting temperature, respectively. The principle of the model is based on thermodynamic functions for multicomponent systems, i.e., mismatch entropy and mixing enthalpy which express the criteria in terms of the number of elements, atomic size differences and the heat of mixing. By combining these thermodynamic quantities with the Miedema's semi-empirical model, AFCR was calculated, and was compared with the experimental results. The GFA factors were also analyzed from viscosity. The R c was derived from transformation diagram of metallic glasses for crystallization while ∆T x was calculated by solving a differential equation expressing the change in free volume with temperature. As a result of these analyses, R c -T g /T m and R-∆T x diagrams were found to fit with the experimental results qualitatively. Furthermore, crystallization temperature (T x ) was also calculated for multicomponent metallic glasses by the modification of the Miedema's binary model for the calculation of T x . The reduced crystallization temperature (T x /T l ), where T l is liquidus temperature, was calculated for evaluating GFA of metallic glasses instead of T g /T m . Some of the calculation methods used in the present study have the advantage giving results as a function of composition; thus, there exists possibility to lead to the prediction of glassy alloys compositions. In this sense, the present calculation methods are completely different to the current method for the development of new metallic glasses relying on the empirical criteria which suggest only appropriate systems and/or elements of the alloys for the achievement of high GFA. In near future, this kind of calculation technique can be used for the prediction of optimal compositions of the metallic glasses with high GFA.

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“…In this connection, the recent work of Simpson and Hodginson [79] is of interest. Using a bubble raft model, Simpson and Hodginson showed that amorphous assemblages near 50-50 at.…”

Section: Jr0mentioning

confidence: 96%

Structure of metallic glasses

Gokularathnam

1974

J Mater Sci

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Metallic glasses or amorphous alloys have been produced by rapid quenching of alloys from the liquid or vapour phase.This paper is a review of the studies on the structure of metallic glasses. The theory of diffraction by amorphous materials is dealt with at length followed by a description of the procedure of obtaining and analysing the RDF of amorphous alloys.Various models have been put forward to explain the structure of the metallic glasses, and these are fully discussed. A dense random packing model or modifications thereof can best explain the structure and range of stability of amorphous alloys.

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Bubble Raft Model for an Amorphous Alloy

Cited by 42 publications

References 11 publications

Two-dimensional matter: order, curvature and defects

Two-dimensional matter: order, curvature and defects

Computer-Aided Development of Multicomponent Metallic Glasses

Structure of metallic glasses

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