Electronic structure behind the mechanical properties of beta-sialons

Journal Article · Sat Aug 01 04:00:00 EDT 1992 · Acta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-7151(92)90185-H· OSTI ID:6958009

Tanaka, I; Nasu, S; Adachi, H; Miyamoto, Y; Niihara, K ^[1]

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1. Osaka University, Ibaraki (Japan) Osaka University, Toyonaka (Japan) Hyogo University of Teacher Education, Yashiro (Japan)

High-purity beta-sialons, Si(6-z)Al(z)O(z)N(8-z) have been fabricated by hot isostatic pressing, and their mechanical properties were examined. Young modulus and Vickers hardness decreased almost linearly with the increase of z-value. The decrease was ascribed to the lattice softening, which as confirmed by Raman spectroscopy. At high temperatures, creep rate of sintered materials and also sintering rate of powders were significantly enhanced with the increase of z-values. Molecular orbital calculations for model clusters were performed by means of discrete-variational (VD) X-alpha method. The electronic structures were quantitatively evaluated by Mulliken population analysis. Strength of covalent bonding expressed as overlap population was found considerably decreased at around the solute atoms, especially at Al atoms, which has been proposed as the electronic mechanism behind the above properties of beta-sialons. 25 refs.

• OSTI ID: 6958009
• Journal Information: Acta Metallurgica et Materialia; (United States), Journal Name: Acta Metallurgica et Materialia; (United States) Vol. 40:8; ISSN 0956-7151; ISSN AMATEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BCC LATTICES
CHALCOGENIDES
COHERENT SCATTERING
CREEP
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DIFFRACTION
ELECTRONIC STRUCTURE
FABRICATION
HOT PRESSING
MATERIALS WORKING
MECHANICAL PROPERTIES
NITRIDES
NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PNICTIDES
PRESSING
RAMAN SPECTRA
SCATTERING
SILICON COMPOUNDS
SILICON NITRIDES
SINTERING
SPECTRA
VICKERS HARDNESS
X-RAY DIFFRACTION
YOUNG MODULUS