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High‐Temperature Elastic Properties of Polycrystalline MgO and Al 2 O 3
Author(s) -
SOGA NAOHIRO,
ANDERSON† ORSON L.
Publication year - 1966
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1966.tb13283.x
Subject(s) - adiabatic process , bulk modulus , thermodynamics , atmospheric temperature range , enthalpy , crystallite , constant (computer programming) , materials science , modulus , poisson's ratio , grüneisen parameter , chemistry , poisson distribution , thermal expansion , composite material , physics , metallurgy , mathematics , statistics , computer science , programming language
Adiabatic bulk modulus, B s , of polycrystalline MgO and Al 2 O 3 was measured from 298° to 1473°K using the resonance technique. The Grüneisen constant, calculated from the measured bulk modulus, was constant over the whole temperature range (1.53 for MgO and 1.34 for Al 2 O 3 ). Another important parameter, , is constant at high temperature and is 3.1 for MgO and 3.6 for Al 2 O 3 . The Poisson's ratio increases linearly with temperature for MgO and Al 2 O 3 . To describe the change of bulk modulus with temperature a theoretical equation was verified by using the foregoing constants. A practical form of this theoretical equation iswhere B s 0 is the adiabatic bulk modulus at 0°K, δ is the quantity , γ is the Grüneisen constant, H is the enthalpy. The experimental data are described very well by this equation, which is equivalent to the empirical equation suggested by Wachtman et al., B s T = B s 0 ‐ CT exp (‐T c /T) , where C and T c are empirical constants.