Modeling the hot forging of nickel-based superalloys: in 718 and alloy 718plus

An internal state variable material model is used to describe the rate– and temperature– dependent large deformation response of the nickel-based superalloys Inconel 718 and Inconel 718 Plus. The current version of the material model describes the elastic-plastic and thermal deformation of metals, having two internal state variables whose evolution equations account for dislocation hardening and static /dynamic recovery processes. Other microstructural features such as recrystallization and grain growth are currenlty being added to the model. Experimental data from mechanical characterization tests of cylindrical and double cone compression specimens are used, respectively, to calibrate the material model and to validate ts predictive capability. In general, the calibrated model predicts well the experimental stress/load levels as well as the rate and temperature dependence of the mechanical response of these superalloys. (AU) © 2010 by The Materials, Metals, & Materials Society. All rights reserved.