Warren M. Garrison Jr., a professor of materials science and engineering at Carnegie Mellon University, has developed a new ultra-strength steel of high fracture toughness that is significantly less expensive to manufacture than existing products.
The new 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.
Garrison said the new steel is one of the outcomes of a Small Business Technology Transfer (STTR) Program, which was funded by the U.S. Navy.
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 aircraft applications. 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.
CMU’s 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 steel developed at CMU 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 researchers report that the next step in the development of the new steel would be to assess its properties in commercial scale heats. 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.
Source: Carnegie Mellon University