Multiscale modeling of discontinuous dynamic recrystallization during hot working by coupling multilevel cellular automaton and finite element method

•Full coupling between 3D multilevel cellular automaton and finite element was achieved.•Oscillation of flow stress during dDRX was analyzed and identified.•Effectively recrystallized nucleation and grain growth behaviors in dDRX were captured.•Macro-heterogeneous deformation and microstructures can be predicted simultaneously. Discontinuous dynamic recrystallization (dDRX) is considered an effective way to obtain fine grain microstructures during hot working of materials with low-to-medium stacking fault energy (SFE). However, to date, investigation and modeling of dDRX in complex hot working processes are not appropriately performed, which hinders further control of the microstructure and forming quality of products during hot working. In this study, a multiscale modeling framework, namely the MCAFE-dDRX model, was constructed by coupling the multilevel cellular automaton (MCA) and finite element (FE) method. The data acquired via the FE method was used as an input for MCA simulation by discretizing the increment in FE time to consider the deformation history of materials. Compared to previous studies where only the effects of constant strain rate and temperature on the deformation of materials are analysed, the MCAFE-dDRX model can evaluate the dDRX microstructure evolution at different Zener-Hollomon levels, which has been validated by hot extrusion in this study. The developed simulation framework facilitates the prediction of microstructure evolution during heterogeneous and non-isothermal deformation of materials.