Modeling of the Mechanical Behavior of a Nickel Alloy by Using a Time-Dependent Thermodynamic Approach to Relaxations of Continuous Media

In this paper, we show the capabilities of a thermodynamicapproach to the relaxation of continuous media to describe the behaviorof the Nickel-based alloy IN738LC submitted to various mechanicalloadings at high temperature (850°C). A preliminarysimple modeling (with one spectrum of relaxation times) does not providesatisfactory results. Microscopic observations of the alloy (Sievert etal., 1997) show the existence of several viscosity domains and we takeone of them into account in our modeling of two spectra of relaxationtimes. The results are much better. Finally, we compare our simulationsto those obtained with the classical elastoviscoplastic modeling ofChaboche and we link these two approaches at the conceptual level.