The continued global increase in air travel requires commercial vehicles to become increasingly more efficient. To minimize fuel consumption and emissions, engines must operate at higher temperatures and higher efficiencies. Therefore, gas turbine hot section materials—specifically materials with lower density and higher temperature capability—are a critical technology.

Silicon carbide ceramic matrix composites (CMCs) are a game-changer for gas turbine hot section materials technology because of their excellent high-temperature mechanical properties, oxidation resistance, and light weight. Extensive development of SiC/SiC CMCs has led to fabrication of gas turbine hot section components, such as CMC shrouds, combustor liners, vanes, and blades. SiC/SiC CMCs consist of three major constituents: SiC fiber reinforcement, fiber coating to allow graceful failure, and SiC matrix. CMCs refer to SiC/SiC CMCs throughout the text.