Ti's New Superalloy Could Soon Take Flight
Ever since the Wright brothers' first flight, researchers have hunted for lighter, stronger materials for aircraft parts and engines. In recent years, much of this search has focused on an exotic metal called gamma titanium aluminide. It is lighter than the nickel- and cobalt-based superalloys used in most aircraft engines, and it can withstand the superhigh temperatures generated by the most efficient jet engines. But there's a problem: The metal is extremely brittle--and shaping it into the thin foils, or sheets, that are mixed with ceramic fibers to form shafts, turbine blades, and other crucial structural parts of an engine has proved impossible.
Now, researchers at Texas Instruments Inc.'s Metallurgical Materials Div. in Attleboro, Mass., have found a potentially economical way of producing the foils. It's a proprietary method for manufacturing the metal at room temperature, or "cold rolling" the foils. Using this process, engineers can tailor the foils for particular uses by controlling the physical properties of the material. The next step is to bring down the manufacturing cost so that the metal can compete with the superalloys--something TI is optimistic it can do. One big benefit: TI claims that with this process, a NASA-Air Force timetable to double jet-engine efficiency by the year 2000 should be met.