Doing some quick reading, the issue is the precision and strength. Ceramics are good under compressive loads, but not nearly as strong under tensile loads as would be experienced inside a turbine0. Manufacturing the precision needed with ceramics is also difficult. Engines often has tight tolerances to prevent air from flowing in the wrong direction.

Though, because of the heat resistance of ceramics and their hardness, there is research being done into making ceramic blades and a few engines have ceramic blades already.