Examination of Inconel 718 Welding Microstructure

Abstract

Inconel 718, a nickel-chromium based austenitic superalloy, is one of the most preferred structural elements in conventional aircraft engines due to the properties of high temperature toughness, manufacturability and fatigue resistance in corrosive environments. Unlike other nickel-based alloys that are equivalent, Inconel 718 stands out with content of γ′′-Ni3Nb phase. This particulates provide the actual structural strengthening mechanism. In this study, the effects of welding process on microstructure and material properties were investigated. In the aircraft engine maintenance process, the welding process is frequently applied to nickel-based superalloys. Following the showing of basic mechanical and physical properties of Inconel 718, the types of cracks occurring in the material due to the high thermal cycle during the process were explained and effects of post welding microstructures such as δ and MxCy phases to the mechanical behavior were also analyzed in detail. In the last section, the treatments that can be performed in the direction of this results for the recovery of material properties were examined.