Microscale modeling of creep deformation and rupture in Nickel-based superalloy IN 617 at high temperature

This manuscript presents the computational modeling and analysis of creep deformation and failure of Nickel-based superalloy, Inconel 617 (IN 617), operating at high temperature. Crystal plasticity finite element (CPFE) approach, considering isothermal and large deformation conditions at the microstructural scale has been extended for creep deformation and rupture modeling of IN 617 at 950 °C. In order to accurately capture the creep strains that accumulate particularly at relatively low stress levels, a dislocation climb model has been incorporated into the CPFE framework. In addition, a cohesive zone (CZ) model is adopted to capture intergranular creep damage, and incorporated into the CPFE framework. The CPFE and the CZ models work in tandem to describe the viscoplastic deformation as well as progressive failure in the material microstructure. The calibration of dislocation climb and CZ parameters is performed based on experimental data. The microstructure model is validated using independent creep experiments performed at various stress levels. Microstructural analysis of the stress and damage distributions as well as their time-dependent evolution is carried out to provide insight into the dominant microscale deformation and failure mechanisms. Creep life predictions are performed to describe rupture life as a function of load amplitude at high temperature.