Alloy 718: Part II, A Versatile Alloy for Critical Applications

Abstract

The second installment of a three-part series traces the expansion of nickel-based superalloy 718 beyond aerospace turbines into critical applications, including large power turbine rotors, rocket engines (notably the Space Shuttle Main Engine), cryogenic systems, nuclear reactors, oil and gas production tooling, and high-strength fasteners. The article highlights how alloy 718's combination of high strength, weldability, corrosion resistance, and performance across extreme temperature ranges—from liquid helium to 1200 °F—drove its adoption. It also details key metallurgical developments, such as delta-phase control and specialized heat treatments, that enabled its use in increasingly demanding environments.