Transactions of the INDIAN CERAMIC SOCIETY Vol. 31 1972
The Effect of Expansion Mismatch on the
Mechanical Properties of Ceramic Materials
G. R. RIGBY
Pages : 18-30
DOI : 10.1080/0371750X.1972.10840793
Abstract
The properties of ceramic materials are dismssed in the light of 1rhether or not they
exhibit expansion mismatch. The principal property examined has been the variation
in modulus of elasticitJ· with temperature orer the range 20 -1400 C. Materials that
show no expansion mismatch lzm•e a high room-temperature modulus but this tends to
decrease continuously with increasing temperature. Further, modulus of elasticity
variations obtained during cooling from J400C are similar to those obtained during
heating. Materials showing expansion mismatch which include magnesia-spinel, mullite
and bauxite based refractory materials, hare a modulus of elasticity that is low at room
temperature but increases with temperature to produce o11e or more maximum values on
the heating curve. The modulus of elasticit_rjtemperature curre obtained during cooling
from 1400°C also exhibits one or more maximum ralues but of higher magnitude and
occurring at lo11el temperatures than those obtained during heating. Modulus of rupture
changes follow a similar pattern to those for modulus of elasticity so that values of this
property at a selected temperature are generally d(fferent when determined during heating
up compared with cooling down. A theory based on the degree of rigidity of silicate films
has been suggested to explain these phenomena and to relate them to their stress/strain
behaviour orer various temperature ranges.
