Carnegie Mellon University (CMU) has developed an ultra-strength steel of high fracture toughness that is significantly less expensive to manufacture than existing products. The new material also has high fracture toughness, particularly during stress corrosion cracking in salt water, making it applicative for the manufacturing of critical parts auch as landing gear for naval aircraft. Defense-Update reports.
When the process is commercialised, the new steel would be more affordable, compared to specialty steels currently used in applicable aerospace industries. This steel contains no cobalt and only a relatively small amount of nickel and therefore is much less expensive than other ultra-high strength steels of high fracture toughness — all of which contain large amounts of cobalt and nickel. While the alloy was developed with Navy aircraft applications in mind, given its low cost and high toughness, it could be used for other applications. The next step in the development would be to assess its properties in commercial scale heats.
One of the objectives of the STTR program was the development of an inexpensive, ultra-strength steel with high fracture toughness that could be used in Navy aviation applications. The new steel also has excellent resistance to crack growth during stress corrosion cracking in salt water. “The rate of crack growth during stress corrosion cracking of the new steel is comparable to that of other ultra-high strength steels of high fracture toughness and is much better than that of low alloy steel 300M, which is the steel used in the landing gear of most commercial aircraft,” said Garrison, who has a patent pending for the new steel.
The new material was developed by Warren M. Garrison Jr., a professor of materials science and engineering at CMU. The company in charge of the STTR program was Navmar Applied Sciences Corporation of Warminster, Pa., which specializes in engineering and technical support for the Department of Defense, the U.S. government and private industry. Garrison worked with Jeffrey Waldman, the scientist in charge of the program at Navmar, and William Frazier, chief scientist at the Air Vehicle Engineering Department of the Naval Air Systems Command. The new material resulted from a U.S. Navy funded Small Business Technology Transfer (STTR) Program.