Fabrication and characterization of UHTCMCs

The materials currently used in aerospace and aviation, such as C/C and C/SiC composites, possess excellent mechanical properties but are limited to a maximum operational temperature of 1600°C (C/SiC) and poorly oxidizing environments (C/C). For more demanding applications, new materials able to withstand extreme temperatures without recession are required. In the framework of the C3harme project, a new class of materials labelled UHTCMCs, consisting of a UHTC matrix reinforced with carbon fibers, has been developed and characterized in order to overcome these challenges. Different fiber reinforcements and sintering parameters have been investigated from the microstructural point of view. The composites were fabricated via slurry infiltration of fiber, using a powder mixture of ZrB2 and SiC; the green pellets were then sintered via hot pressing. Extensive microstructural analysis was carried out on the sintered samples, showing how the sintering parameters and the choice of the fibers are crucial to obtain full densification without jeopardizing the fibers integrity and permit adequate load transfer.