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99-79

For Release: October 8, 1999

Pam Caswell
NASA Glenn Research Center
(Bus: 216/433-5795)

Lori J. Rachul
NASA Glenn Research Center
(Bus: 216/433-8806)

NASA Aerospace Materials Processing Technology Transferred to Industry

Fabrication techniques for making space-age engine exhaust components mean improved performance and gas mileage for tomorrow's aerospace planes and, perhaps, for the family car.

The techniques were developed by an international team of researchers to handle the space-age, intermetallic alloy material, titanium aluminide (TiAl). Structural engineers from NASA Glenn Research Center and their team selected TiAl in sheet form to be used for the truss core portion of the exhaust nozzle of a proposed high-speed civil transport because it is light weight, stiff and strong at high temperatures.

The alloy had been difficult to form into usable parts because standard alloy forming processes degraded some of its best features. Further, its high material and production costs made it unattractive to manufacturers. The team developed and tested fabrication processes for shaping and joining the thin, 0.6-millimeter (0.025-inch) thick sheets of TiAl, with particular attention paid to reducing production cost. The processes include sheet rolling, relatively low-temperature hot forming, joint brazing and bonding, and heat treatment after machining to relieve stresses around rivet holes.

"The team's work shows that this intermetallic alloy does not need the costly fabrication processes typically used for intermetallic components," said Paul Bartolotta, Glenn's principle investigator and team lead for the project. "Our process doesn't require a vacuum, uses relatively low shaping and forming temperatures and produces more uniform parts than could be produced with other forming methods."

The practicality of the techniques was proven when BF Goodrich Aerospace, Chula Vista, CA, successfully manufactured the truss core from TiAl sheet in its own plant using its regular production equipment. The result was a truss core with the soundness and strength of similar parts made under the special conditions of a research laboratory. The truss core was made from separately formed corrugations, or hats, covered top and bottom with flat sheets of the same material. In cross section it looks much like a corrugated box.

"This NASA Glenn contract has greatly assisted us in the development of production processing of this new material system. It will in turn support the potential use of TiAl…in the thermal protection system for a reusable launch vehicle," said John Meaney, BF Goodrich Aerospace project manager for the program.

Cast and wrought TiAl is already being used in high-end, high-performance cars and is being considered for use in commercial aircraft engines. The inexpensive forming techniques may allow the wrought form of this lightweight alloy to be used in valve stems, heat shields and exhaust system components, bringing lighter-weight and, so, more fuel-efficient cars.

The Glenn structures and materials research program is part of NASA's continuing research effort to provide the materials for tomorrow's aerospace vehicles. Titanium aluminide alloy development was conducted under its High Speed Research Propulsion project with research partners Pratt & Whitney, West Palm Beach, FL, and Plansee GmbH, Lechbruck, Germany. The technology from that program will be used to help design economical, lightweight TiAl components for next-generation space vehicles such as the reusable launch vehicle, VentureStar.

Note to Editors/News Directors: For an interview with Paul Bartolotta or to obtain photos supporting this release, media representatives may contact Pam Caswell of the Glenn Media Relations office at 216/433-5795. Print-quality images are available at

http://www.lerc.nasa.gov/WWW/PAO/pressrel/99_79addm.htm

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