Simulation of Austenite-to-ferrite Transformation in Deformed Austenite by Crystal Plasticity Finite Element Method and Multi-phase-field Method

概要

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A simulation model to describe the austenite-to-ferrite transformation in the deformed austenite phase is developed using the crystal plasticity finite element and multi-phase-field methods. Using the developed model, we simulate the plastic deformation behavior of the polycrystalline austenite phase during plane strain compression and the subsequent isothermal austenite-to-ferrite transformation. The ferrite nucleation behaviors on the elongated austenite grain boundary and the deformation bands formed in the austenite grain are estimated on the basis of the classical nucleation theory. In this study, the effects of plastic deformation of the austenite phase and the holding temperature on the transformation kinetics and the ferrite grain size are investigated. The simulation results show that transformation is accelerated with an increase in the strain in the austenite phase. Furthermore, it is confirmed that ferrite grain refinement occurs by the enhancement of ferrite nucleation within the deformed austenite grain interior and by the suppression of ferrite grain growth due to hard impingement.