Thermal-mechanical limitations of oxide/oxide ceramic matrix composites and prospects for improvement

Kurzfassung

Lightweight, oxide/oxide ceramic matrix composites (OxCMC) are attractive materials for exhaust gas exposed turbine engine components. Despite many favorable physical-chemical properties, their limited high-temperature mechanical strength and creep resistance, but also limited knowledge on their aging behavior are frequently obstacles for their application in demanding environments and high-performance applications. Moreover, reproducible and scalable manufacturing processes are considered mandatory to exploit the full potential of OxCMC. Various studies on OxCMC consisting of different oxide fibers and matrices based on Al2O3 and mullite were performed to identify key degradation effects and possible mitigation strategies. Chemical modification of oxide matrices as well as the application of thick thermally sprayed protective coatings revealed the potential for increased application temperatures. In terms of OxCMC manufacturing technologies, DLR’s recently introduced vacuum-assisted textile infusion processes IFOX offer promising time- and cost efficiency manufacturability as well as improved material properties with low scattering.