The US Air Force is testing materials produced through ceramic additive manufacturing to advance their potential future use in hypersonic flight vehicles. They are testing additively manufactured silicon oxycarbide (SiOC) materials.The geometric complexity of components that can be produced through additive manufacturing in conjunction with the refractory nature of ceramics holds enormous potential for a variety of future Air Force applications. One such possible application is hypersonic flight, which exposes materials to extreme environments including high temperatures.
The potential of the HRL-produced materials for demanding Air Force applications became apparent while Aerospace Systems Directorate scientists were searching for new thermocouple radiation shields. The SiOC materials were produced through an additive manufacturing process utilizing a pre-ceramic resin. Following part fabrication, the pre-ceramic resin was heat treated to convert the component to a fully ceramic state. AFRL scientists became interested in HRL’s novel process taking advantage of state-of-the-art 3D printing capabilities and pre-ceramic resin chemistry as well as the possible performance of the final SiOC materials at high temperatures.
“If a material can withstand those temperatures – roughly 3,200 degrees Fahrenheit – it could be used for hypersonic aircraft engine components like struts or flame holders,” said Jamie Szmodis, a hypersonic research engineer with the Aerospace Systems Directorate.
Hypersonic flight is a compelling area of study for the U.S. and international aerospace industry. Current aircraft fly at supersonic speeds, over 768 miles per hour, or MACH 1. If achieved, hypersonic fight, that is speeds exceeding Mach 5, would allow for much faster military response times, more advanced weapons and drastically decreased travel times for the military and commercial sectors with speeds over 4,000 miles per hour.
During the course of their collaborative study, AFRL and HRL pushed the additively manufactured components far beyond their design envelope. The data which emerged from this extreme testing provided the partners with valuable information that is currently being utilized to guide the production of next-generation additively manufactured ceramics. These recommendations and further advances by HRL have the potential to produce materials that can meet the hypersonic requirements.