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

尖锐的前缘和鼻锥在高超声速飞行中有利于飞行控制，但比钝的要承受更高的温度。因此，在高超声速系统中增强飞行控制需要能够在2000摄氏度以上工作的材料，具有最小的侵蚀/氧化，同时还表现出良好的导热性和抗热震性。超高温陶瓷基复合材料（uhtcmc）是少数能够长时间承受这种环境的材料之一，克服了单片UHTCs的低韧性。然而，传统的生产高质量uhtcmc的方法，如液体熔体渗透或化学蒸汽渗透，是时间和成本密集的。机械铸造是一种增材制造的形式，在热处理交联粘合剂材料之前，将陶瓷浆料/油墨沉积并固化为净形组件或预浸层，是一种新型且更经济的生产组件的方法，正在由CASC团队开发。高熵或熵稳定超高温碳化物是一类新的陶瓷，其中在超高温碳化物中通常发现的多种过渡金属被结合成单相结晶溶液。早期的研究表明，随着熔融温度的提高和抗氧化性的提高，高熵超高温碳化物的潜在性能要高于单个组分。这个博士提案提供了一个令人兴奋的机会，将机器人铸造和熵稳定超高温超导的进步结合起来，回答两个关键问题。1. 将3D打印的过渡金属粉末在酚醛/碳屈服树脂中转化为致密的UHTCMC基体是否可行？, 2。如果在同一过程中组合多个过渡金属粉末，是否可以生产出熵稳定的超高温cmc，其热机械性能优于单独的二元过渡金属粉末？

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?