Ultrahigh-Temperature Materials for Jet Engines
- PDF / 1,236,466 Bytes
- 9 Pages / 612 x 792 pts (letter) Page_size
- 50 Downloads / 162 Views
Ultrahigh-
Temperature Materials for Jet Engines
J.-C. Zhao and J.H. Westbrook, Guest Editors Abstract This introductory article provides the background for the September 2003 issue of MRS Bulletin on Ultrahigh-Temperature Materials for Jet Engines. It covers the need for these materials, the history of their development, and current challenges driving continued research and development.The individual articles that follow review achievements in four different material classes (three in situ composites—based on molybdenum silicide, niobium silicide, and silicon carbide, respectively—and high-melting-point platinum-group-metal alloys), as well as advances in coating systems developed both for oxidation protection and as thermal barriers. The articles serve as a benchmark to illustrate the progress made to date and the challenges ahead for ultrahigh-temperature jet-engine materials. Keywords: coatings, composites, ductility, jet engines, oxidation, oxides, platinumgroup-metal alloys (PGM alloys), silicides, strength, structural materials, thermal-barrier coatings, toughness, ultrahigh-temperature materials.
This year marks the centennial of the Wright brothers’ first flight. In the second half of the last century, aircraft powered by jet engines came to dominate both civilian and military flights, and they continue to have tremendous impact on the economy and on our lives (e.g., aircraft turbine engines are the single largest U.S. export product). The history of the jet engine goes back much farther than one would suppose. Jacques Etienne Montgolfier was the first to propose reaction propulsion for aircraft in 1783. His concept was intended for a balloon rather than an airplane and more for steering than main propulsion. The first patent for a turbine engine appeared in 1791; it was intended for use on a horseless carriage (automobile). Charles de Leuvrié first suggested the idea for a jet-powered monoplane in 1865, but it was not until 1928 that Frank Whittle, a 21-year-old Royal Air Force cadet, advanced the idea of jet propulsion for aircraft in a published thesis. Although his concept was rejected by the authorities of the time, he persevered and by April 12, 1937, had built and 622
successfully tested his first turbo-jet engine. Whittle’s engine first powered an airplane (the Gloster E2) on May 15, 1941. Meanwhile, an independent parallel effort was going forward in Germany. Hans von Ohain obtained a patent for a jet engine on November 10, 1935. With backing from Ernst Heinkel, he built the He S3B engine, which successfully powered an airplane, the He 178, on August 27, 1939. Both of these developments came too late to have a significant impact on World War II, although some military jets were flown in the 1940s. The commercial significance of the new mode of power was apparent, and in 1952, the British Overseas Airways Co. (BOAC) inaugurated the first scheduled jet passenger service. In 1992, Ohain and Whittle shared the Draper Prize for “early jet development and contributions to mankind.” Readers may be in
Data Loading...
