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 thermodynamic approach to the relaxation of continuous media to describe the behavior of the Nickel-based alloy IN738LC submitted to various mechanical loadings at high temperature (850 degreesC). A preliminary simple modeling (with one spectrum of relaxation times) does not provide satisfactory results. Microscopic observations of the alloy (Sievert et al., 1997) show the existence of several viscosity domains and we take one of them into account in our modeling of two spectra of relaxation times. The results are much better. Finally, we compare our simulations to those obtained with the classical elastoviscoplastic modeling of Chaboche and we link these two approaches at the conceptual level.