MODELING DYNAMIC RECRYSTALLIZATION OF METALS USING CRYSTAL PLASTICITY

International audienceInconel alloys for aerospace motor applications are hot forged and their final properties are mainly control by the homogeneity of the grain size. In hot forging conditions, dynamic recrystallization occurs and the prediction of the final microstructure requires an accurate modeling of this deformation mechanism. A polycrystal modeling, coupling CPFEM and recrystallization models, have been developed using a 3D EBDS description of a representative volume. With only a few material parameters, it is then possible to predict mechanical behavior during hot forging and grain size evolution. INTRODUCTION: Inconel 718 is usually hot forged between 925 and 1150°C with the objective to control the homogeneity of the grain size and the final mechanical properties. At temperatures above 1,000°C, the alloy is a fcc single-phase as the phase is totally dissolved. Thomas et al. [2004] showed that dynamic recrystallization is the main mechanism controlling the microstructure evolution. A polycrystalline model is developed to account for dynamic recrystallization. A 3D EBSD mapping of a representative volume is reconstructed from serial polished sections. Its behavior is simulated by coupling a crystal plasticity finite element model (CristalECP) with a 3D recrystallization cellular automaton (RecUPS). The two models work with sequences of deformation and recrystallization steps. CristaECP is based on the theory of continuous dislocations and on physical constitutive laws (Erieau [2004]). The polycrystalline model is implemented in Abaqus T