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Accession Number ADA563245
Title Performance Characterization of Polyimide-Carbon Fiber Composites for Future Hypersonic Vehicles.
Publication Date Aug 2010
Media Count 37p
Personal Author J. C. Grunlan J. N. Reddy K. R. Rajagopal
Abstract The US military has initiated research and development progress to develop hypersonic vehicles in the Mach 5-15 range. Two broad categories are being considered, namely: (i) vehicles that fly at low altitudes for short times (minutes) over distances of hundreds of miles and (ii) flights that are global and cover lower space orbits over periods of hours. Specifically, Air Force future vehicles need to be able to reach anywhere in the world in one hour (Vista 25 program). Aerodynamic heating of the vehicle exterior depends on the altitude, but generally exterior vehicle temperatures are proportional to the square of the Mach number. The primary structures of hypersonic vehicles need to be lightweight, strong and thermally durable. Transition-metal carbides, referred to as ultra-high temperature (UHT) materials, are interesting because they are refractory materials with the highest known melting points (that in many cases exceed 2600 deg. C). Applications for UHT materials challenge the survivability of many known materials currently in use. Unfortunately, the synthesis of the refractory transition-metal carbides requires high temperatures that can exceed 1700 C. The in-situ synthesis of transition-metal carbides, in an argon atmosphere using transition-metal halide salts solution- processed with polymer matrices, is described here as a low temperature method for making UHT carbides. The AFR-PEPA-N polyimide-carbon fiber system is the leading candidate as the starting material. This polymer system is already being processed for leading edge primary structures and engine components for present and future stealth aircraft.
Keywords Aerodynamic heating
Carbides
Carbon fibers
Curing
Degradation
Environment induced degradation mechanisms
Hypersonic vehicles
Isothermal cure
Physical properties
Polyimide plastics
Transition metal carbides
Transition metal compounds
Ttmp(Time temperature mechnanical properties) relationships
Uht(Ultrahigh temperature) materials

 
Source Agency Non Paid ADAS
NTIS Subject Category 51C - Aircraft
99C - Polymer Chemistry
71F - Composite Materials
46B - Fluid Mechanics
Corporate Author Texas Engineering Experiment Station, College Station.
Document Type Technical report
Title Note Final rept. 1 Apr 2007-31 Jul 2010.
NTIS Issue Number 1226
Contract Number FA9550-07-1-0285

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