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Title: Structural properties of Y2O3–Al2O3 liquids and glasses: An overview

Abstract

Liquids in the system Y2O3- Al2O3 have been the subject of considerable study because of the reported occurrence of a first-order density and entropy-driven liquid-liquid phase transition (LLPT) in the supercooled liquid state. The observations have become controversial because of the presence of crystalline material that can be formed simultaneously and that can mask the nucleation and growth of the lower density liquid. The previous work is summarized here along with arguments for and against the different viewpoints. Also two studies have been undertaken to investigate the LLPT in this refractory system with emphasis on determining the structure of unequivocally amorphous materials. These include the in situ high energy X-ray diffraction (HEXRD) of supercooled Y2O3 - Al2O3 liquids and the low frequency vibrational dynamics of recovered glasses. Manybody molecular dynamics simulations are also used to interpret the results of both studies. The HEXRD measurements, combined with aerodynamic levitation and rapid data acquisition techniques, show that for the 20 mol% Y2O3 (i.e. AlY20) liquid there is a shift in the position of the first peak in the diffraction pattern over a narrow temperature range (2100-1800 K) prior to crystallization. Microbeam Raman spectroscopy measurements made on AlY20 glasses clearly show contrasting spectramore » in the low frequency part of the spectrum for low(LDA) and high-density (HDA) glassy regions. The molecular dynamics simulations identify contrasting coordination environments around oxygen anions for the high- (HDL) and low-density (LDL) liquids. (C) 2014 Elsevier B.V. All rights reserved.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1248049
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Non-Crystalline Solids; Journal Volume: 407
Country of Publication:
United States
Language:
English
Subject:
Containerless techniques; Liquid structure; Polyamorphism; Raman spectroscopy; X-ray diffraction

Citation Formats

Wilding, Martin C., Wilson, Mark, McMillan, Paul F., Benmore, Chris J., Weber, J. K.R., Deschamps, Thierry, and Champagnon, Bernard. Structural properties of Y2O3–Al2O3 liquids and glasses: An overview. United States: N. p., 2015. Web. doi:10.1016/j.jnoncrysol.2014.09.044.
Wilding, Martin C., Wilson, Mark, McMillan, Paul F., Benmore, Chris J., Weber, J. K.R., Deschamps, Thierry, & Champagnon, Bernard. Structural properties of Y2O3–Al2O3 liquids and glasses: An overview. United States. doi:10.1016/j.jnoncrysol.2014.09.044.
Wilding, Martin C., Wilson, Mark, McMillan, Paul F., Benmore, Chris J., Weber, J. K.R., Deschamps, Thierry, and Champagnon, Bernard. Thu . "Structural properties of Y2O3–Al2O3 liquids and glasses: An overview". United States. doi:10.1016/j.jnoncrysol.2014.09.044.
@article{osti_1248049,
title = {Structural properties of Y2O3–Al2O3 liquids and glasses: An overview},
author = {Wilding, Martin C. and Wilson, Mark and McMillan, Paul F. and Benmore, Chris J. and Weber, J. K.R. and Deschamps, Thierry and Champagnon, Bernard},
abstractNote = {Liquids in the system Y2O3- Al2O3 have been the subject of considerable study because of the reported occurrence of a first-order density and entropy-driven liquid-liquid phase transition (LLPT) in the supercooled liquid state. The observations have become controversial because of the presence of crystalline material that can be formed simultaneously and that can mask the nucleation and growth of the lower density liquid. The previous work is summarized here along with arguments for and against the different viewpoints. Also two studies have been undertaken to investigate the LLPT in this refractory system with emphasis on determining the structure of unequivocally amorphous materials. These include the in situ high energy X-ray diffraction (HEXRD) of supercooled Y2O3 - Al2O3 liquids and the low frequency vibrational dynamics of recovered glasses. Manybody molecular dynamics simulations are also used to interpret the results of both studies. The HEXRD measurements, combined with aerodynamic levitation and rapid data acquisition techniques, show that for the 20 mol% Y2O3 (i.e. AlY20) liquid there is a shift in the position of the first peak in the diffraction pattern over a narrow temperature range (2100-1800 K) prior to crystallization. Microbeam Raman spectroscopy measurements made on AlY20 glasses clearly show contrasting spectra in the low frequency part of the spectrum for low(LDA) and high-density (HDA) glassy regions. The molecular dynamics simulations identify contrasting coordination environments around oxygen anions for the high- (HDL) and low-density (LDL) liquids. (C) 2014 Elsevier B.V. All rights reserved.},
doi = {10.1016/j.jnoncrysol.2014.09.044},
journal = {Journal of Non-Crystalline Solids},
number = ,
volume = 407,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 2015},
month = {Thu Jan 01 00:00:00 EST 2015}
}