Selection and Performance of AM Superalloys for High-Speed Flight Environments

Abstract In developing the Wire + Arc Additive Manufacturing (WAAM) process for the manufacture of components used in high-speed flight environments, a selection process for suitable alloys was devised. Using elevated temperature material properties from literature sources, creep-resistant alloys were down selected based on the requirement for service in a high temperature, high stress environment and the need for an alloy suitable for additive manufacturing using a wire-arc process. Down selected alloys Inconel 718 (IN718), Rene 41 (RE41), Haynes 188 (H188) and Inconel 625 (IN625) were deposited by a plasma transferred arc WAAM process in an oxygen-controlled environment. The structures were built then underwent mechanical testing. The performance of as deposited material was then compared against wrought alloy data from literature. Tensile testing at room temperature revealed a correlation with similarly strengthened IN718 & RE41, but no correlation with solution strengthened H188 and IN625. Results revealed that the AM material did not meet the wrought strength and with performance varying depending on each alloy’s strengthening mechanism. Results illustrate the need for further processing to return the mechanical performance to wrought values.