Complete elastic tensor for muilite (∼2.5Al2O3·SiO2) to high temperatures measured from textured fibers

James W. Palko, Ali Sayir, Stanislav V. Sinogeikin, Waltraud M. Kriven, Jay D. Bass

Research output: Contribution to journalArticlepeer-review

Abstract

Directionally solidified mullite fibers have been grown by the laser-heated, float-zone method from starting materials with a nominal composition of 3Al2O3·2SiO2. The fibers used in this study have large single-crystal regions with composition 2.5Al2O3·SiO2 and [001] fiber axis orientation. The complete elastic tensor of these samples has been determined by Brillouin spectroscopy at room temperature and elevated temperatures up to 1200°C. Isotropic moduli (bulk, shear, and Young's) have been calculated using the Voigt-Reuss-Hill averaging scheme. The room-temperature values obtained are KVRH = 173.5 ± 6.9 GPa, GVRH = 88.0 ± 3.5 GPa, EVRH = 225.9 ± 9.0 GPa. All moduli show gradual, linear decreases with temperature. The temperature derivatives obtained for the equivalent, isotropic moduli are dKVRH/dT = -17.5 ± 2.5 MPa/°C, dGVRH/dT = -8.8 ± 1.4 MPa/°C, dEVRH/dT = -22.6 ± 2.8 MPa/°C. Substantial differences between bulk properties calculated from the single-crystal measurements in this study and the properties reported in the literature for polycrystalline sintered mullite are identified, indicating the importance of factors such as microstructure, intergranular phases, and composition to the elasticity of mullite ceramics.

Original languageEnglish (US)
Pages (from-to)2005-2012
Number of pages8
JournalJournal of the American Ceramic Society
Volume85
Issue number8
DOIs
StatePublished - Aug 2002

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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