Robocasting entropy stabilised ultra-high temperature ceramic composites for hypersonic applications.

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Sharp leading edges and nose cones are advantageous for flight control in hypersonic flight but suffer much higher temperatures than blunt ones. Hence enhanced flight control in the hypersonic regime requires materials capable of operating above 2000 C with minimal erosion/oxidation while also showing good thermal conductivity and thermal shock resistance. Ultra-high temperature ceramic matrix composites (UHTCMCs) are one of the few materials able to withstand this environment for prolonged periods overcoming the low toughness of monolithic UHTCs. Traditional methods of producing high-quality UHTCMCs such as liquid melt infiltration or chemical vapour infiltration are however time and cost-intensive. Robocasting, a form of additive manufacture in which a ceramic slurry/ink is deposited and cured as a net shape component, or pre-preg ply, prior to heat treatment to cross-link the binder material, is a novel and more affordable method of producing components that is under development by the CASC team. High entropy or entropy stabilised UHTCs are a new class of ceramic in which multiple transition metals typically found in UHTCs are combined into a single-phase crystalline solution. Early research has shown the potential performance of high entropy UHTCs to be greater than individual components with increased melting temperatures and oxidation resistance. This PhD proposal provides an exciting opportunity to combine the advances in robocasting and entropy-stabilised UHTCs to answer two key questions. 1. Is it feasible to convert 3D printed transition metal powders within a phenolic / carbon yielding resin into a densified UHTCMC matrix? And, 2. If multiple transition metal powders are combined in the same process can an entropy stabilised UHTCMC be produced with better thermo-mechanical properties than binary transition metal powders alone?