AM Functionally Graded Graded Randomes for Hypersonic Vehicles

The innovation described in the Phase I proposal “Additive Manufacturing and Characterization of Radome Materials” is to achieve the first fiber-reinforced ceramic composite manufactured with selective laser sintering (SLS) Additive manufacturing (AM). The innovation is twofold, (i) development of a novel rapid-cured fiber-reinforced preceramic composite material that can be (ii) additively manufactured via SLS and cured in-situ. The project will use a new SOTA SLS 3D printer developed by Dr. Beaman’s lab at the University of Texas at Austin. The printer, referred to as “Laser Additive Manufacturing Pilot System” or LAMPS, utilizes 40 heaters, 3 quartz lamps, two MWIR cameras, and one visual camera for in situ monitoring. LAMPS is a uniquely capable system for 3D printing thermosets, combining its cutting-edge optical system, in-situ monitoring, and precisely-controlled heating capabilities. While KAI will be employing SLS there will be no actual sintering or melting of the preceramic powder system. Instead the laser will be used to activate a catalyst within the powder system causing a partial crosslinking to occur. The preceramic system will be a blend of solventless polysiloxane with ceramic microfibers and a laser-activated catalyst. The AM process will result in a stable preceramic greenbody part with an excellent resolution of 120-150 µm. Pyrolysis of the printed greenbody will be necessary to achieve the final functionally graded SiOC ceramic radome. For Phase I A total of three prototype ceramic composites will printed and undergo preliminary characterization. The materials will be examined for chemical composition, heat capacity, and thermal expansion metrics. Additionally, comprehensive methods for further high temperature (500 to 1500°C) will be identified and/or developed for more extensive materials characterization in Phase II. The successful conclusion of Phase I will be a proof of concept for KAI’s innovative AM technique for ceramic components. Phase II will see further exploration of this concept and KAI will expand its ceramic AM portfolio to include SiC, SiCN, and SiON. Additionally, in Phase II, fillers which may positively impact the pyrolysis chemistry during ceramic conversion will be fully considered. KAI will use Phase II to validate the mechanical, thermal, and dielectric character of ceramics developed in Phase I as well as new ceramics developed in Phase II. Ultimately KAI has a detailed commercialization plan in place for Phase III rollout. Emphasis on Phase III will be the sale or lease of KAI technology to US Missile Defense contractors while maintaining the capability of manufacturing small batch orders of functionally graded hypersonic radomes for the US Army. Upon the transfer of technology to appropriate defense contractors, KAI may pivot its technology to offer commercially available AM of ceramic and thermoset parts for the aerospace, oil and gas, and automotive industries.