Mechanical tests provide important information about the properties and
behaviour of materials. Basic tests include the measurement of flexural
strength and in case of refractory materials, the measurement of flexural
strength at high temperatures as well. The dependence of flexural strength on
the temperature of ceramic materials usually exhibits a constant progression
up to a certain temperature, where the material starts to melt and so the
curve begins to decline. However, it was discovered that ceramic mullitic
material with a 63 wt.% of Al2O3 exhibits a relatively significant maximum
level of flexural strength at about 1000?C and refractory mullitic material
with a 60 wt.% of Al2O3 also exhibits a similar maximum level at about
1100?C. The mentioned maximum is easily reproducible, but it has no
connection with the usual changes in structure of material during heating.
The maximum was also identified by another measurement, for example from the
progression of the dynamic Young?s modulus or from deflection curves. The aim
of this work was to analyse and explain the reason for the flexural strength
maximum of mullitic materials at high temperatures.
Measuring absorptivity of ceramic materials at high temperatures in Gyrotron Ceramics Sintering System
