Dynamic Recrystallization Modeling during Hot Forging of a Nickel Based Superalloy

Abstract

A crystalline modeling of deformation implemented in the Finite Element code Abaqus® coupled to a recrystallization Cellular Automaton code is proposed and applied to the hot forging process. A sequential modeling is used in order to obtain a better understanding of the experimental observations and to improve our knowledge of the dynamic recrystallization process. Modeling is performed on aggregates built up from Electron Back Scattered Diffraction measurements. At the deformation temperature, the material presents two phases with a γ matrix of FCC structure and a γ’ hardening phase under a precipitate shape (Ni3(Ti,Al)) of SC structure. The crystalline approach can describe the interactions between the two phases and can compute the evolution of the local strain and stress fields as well as the dislocation density and the lattice rotation in the different grains. A Cellular Automaton algorithm is used for simulating the microstructure evolution during dynamic recrystallization. Nucleation and grain boundary mobility depend on the misorientation and on the local variation in stored energy. This presentation mainly details the different assumptions introduced in the recrystallization code and their influences on the microstructure evolution.