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Composition and polyamorphism in supercooled yttria-alumina melts

Greaves, GN and Wilding, MC and Langstaff, D and Kargl, F and Hennet, L and Benmore, CJ and Weber, JKR and Van, QV and Majerus, O and McMillan, PF (2011) Composition and polyamorphism in supercooled yttria-alumina melts. Journal of Non-Crystalline Solids, 352 (2), pp. 435-441. ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. DOI: 10.1016/j.jnoncrysol.2010.06.072.

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Abstract

By extending recent work on liquid-liquid transitions in supercooled yttria-alumina AYx liquids we draw attention to the compositional dependence of the structure factor of the high density liquid, arguing that this is sufficiently sensitive to discriminate between liquids at the level of a few %. Comparing structure factor differences between liquids of different compositions and in the same liquid AY20 between high and low temperatures straddling the transition at 1788 K between a high density liquid (HDL) and a low density liquid (LDL) enables compositional phase separation to be ruled out. It points instead to kinetic changes in polyhedral configurational order being the drivers for this polyamorphic transformation. Rotor behaviour observed in levitated liquid drops used in the high temperature experiments enables the reversibility of the LLT transition (LLT) and the associated changes in entropy and density to be identified. Evidence for critical-like behaviour in the structural relaxation time and in the fluctuation correlation length is presented. By re-examining recent work which failed to find the structural and thermal signatures for the LLT in liquid AY20 at 1788 K we present evidence for the LLT occurring instead in liquid AY15 at 1940 K, suggesting that the liquid-liquid transition temperature in AYx liquids decreases with increasing yttria content. (C) 2010 Elsevier B.V. All rights reserved.

Document Type:Article
Title:Composition and polyamorphism in supercooled yttria-alumina melts
Authors:
AuthorsInstitution or Email of Authors
Greaves, GNAberystwyth Univ, Ctr Adv Funct Mat & Devices, Inst Math & Phys, Aberystwyth SY23 3BZ, Dyfed, Wales;UCL, Dept Chem, London WC1H 0AJ, England; UCL, Mat Chem Ctr, London WC1H 0AJ, England
Wilding, MCAberystwyth Univ, Ctr Adv Funct Mat & Devices, Inst Math & Phys, Aberystwyth SY23 3BZ, Dyfed, Wales
Langstaff, DAberystwyth Univ, Ctr Adv Funct Mat & Devices, Inst Math & Phys, Aberystwyth SY23 3BZ, Dyfed, Wales
Kargl, FAberystwyth Univ, Ctr Adv Funct Mat & Devices, Inst Math & Phys, Aberystwyth SY23 3BZ, Dyfed, Wales; Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
Hennet, LCNRS CEMHTI, F-45071 Orleans 2, France
Benmore, CJArgonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA
Weber, JKRArgonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA;Mat Dev Inc, Arlington Hts, IL 60004 USA
Van, QVAberystwyth Univ, Ctr Adv Funct Mat & Devices, Inst Math & Phys, Aberystwyth SY23 3BZ, Dyfed, Wales
Majerus, OEcole Natl Super Chim Paris, F-75231 Paris, France
McMillan, PFUCL, Dept Chem, London WC1H 0AJ, England ;UCL, Mat Chem Ctr, London WC1H 0AJ, England
Date:15 January 2011
Journal or Publication Title:Journal of Non-Crystalline Solids
Refereed publication:Yes
In Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:352
DOI:10.1016/j.jnoncrysol.2010.06.072
Page Range:pp. 435-441
Publisher:ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Status:Published
Keywords:Diffraction and scattering measurements; Supercooled liquids; Glass formation; Phases and equilibria; Structure; Fluctuations; Critical phenomena
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:other
DLR - Research area:Raumfahrt
DLR - Program:R - no assignement
DLR - Research theme (Project):R -- no assignement
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Physics in Space
Deposited By: Dr Florian Kargl
Deposited On:25 Aug 2011 10:49
Last Modified:07 Feb 2013 20:33

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