Mullite (3Al(2)O(3).2SiO(2)) based composites have excellent mechanical and
thermal properties. The same characteristics that give mullite good resist
ance to plastic deformation also make its sintering difficult. Yttria is on
e of the most commonly used additives to reduce sintering temperatures in m
ullite. Additionally vitreous silicates (Y2Si2O7) could improve ductility.
In this work we have used mullite samples with various amounts of Y2O3 (0,
5 and 9 wt.%). Details of processing and characterization of these composit
es have been the subject of a previous publication. We have compared the du
ctility of these composites by means of compressive deformation tests at el
evated temperatures. Creep tests were performed at temperatures between 130
0 and 1400 degreesC, in air, in a stress range of 0.69 to 34.5 MPa.