Improving creep resistance of nickel-based superalloy Inconel 718 by tailoring gamma double prime variants

Inconel 718 is a widely used nickel-based superalloy in aircraft engines during the past decades, whose elevated temperature strength derives from disc-shaped gamma double prime (γ″) in three perpendicular variants plus less spherical gamma prime (γ′) precipitates. In present work, we observed an abnormal γ″ variant with tailored orientation and shape in directly aged cold-rolled Inconel 718, creep tests proved its substantial benefits in improving creep resistance at 650 °C superior to commonly perpendicular γ″ variants. The results can provide new insights for processing optimization and second-particle configuration design to maximize the strengthening effect of γ″ phase in 718-type superalloys.