Physically Based Constitutive Model for Viscoplastic Deformation of Inconel718 at High Strain Rates and Temperatures

In the cutting process of nickel-based superalloys, because of the high strain rate and cutting temperature, the cutting deformation is complex and there exist hardening and softening phenomena. Therefore, the present study developed a physically-based constitutive model, which represents the mechanical response of a material at a given microstructure in terms of dislocation glide to describe the deformation behaviors of Inconel718. The established model also describes evolution equations for internal variables characterizing the microstructure. The internal variables are related to the dislocation density. Comparisons between the experimental results and those predicted employing different models [a physically-based constitutive model has been established in the present work and Johnson-Cook (JC) constitutive model] indicate that the established model can accurately characterize the deformation behaviors for Inconel718 at high strain rates and temperatures.