Why aren't ceramics used in turbines? I have seen that ceramics take a lot of heat to melt (3240º F). So, I'm wondering, why aren't ceramics used as the compressor levels in turbines? Is there something to do with the strain? or is ceramic too heavy? Is it something to do with the way the crystals align?
Ceramic materials are starting to be used in jet engines.  E.g. the LEAP-1A is using a few ceramic matrix composite in the high pressure turbine.   (http://aviationweek.com/mro/ceramic-composites-enter-service). Future designs will likely expand the use of CMCs (e.g. http://www.geaviation.com/press/ge90/ge90_20150303.html)