[SY-F7] Symposium F-7

[SY-F7] Two-dimensional Simulation of Cyclic Phase Transformation in Fe-C-Mn-Si Alloy using Non-equilibrium Multi-Phase-Field Model

^○Masahito Segawa¹, Nomoto Sukeharu¹, Akinori Yamanaka² (1.ITOCHU Techno-Solutions Corporation, Japan, 2.Division of Advanced Mechanical Systems Engineering, Institute of Engineering, Tokyo University of Agriculture and Technology, Japan)

Multi-phase-field (MPF) method incorporating CALPHAD database has attracted much attention as a powerful numerical tool for simulating microstructure evolutions in various metallic materials. Transformation modes and diffusion behavior of substitutional solute atoms strongly depend on temperature and chemical compositions of the alloy especially in multi-component steels, i.e. an Fe-C-Mn ternary alloy. Therefore, we need to use a robust MPF model which can simulate the transition of transformation mode and the complex diffusion behavior. Recently, the MPF model with finite interface dissipation has been proposed (Hereafter, the MPF model is called as the non-equilibrium MPF (NEMPF) model). The attractive advantages of the NEMPF model are its computational efficiency and flexibility for simulating microstructure evolutions under strong non-equilibrium interface condition without the equal chemical potential assumption. In the previous study, we investigated the cyclic γ → α and α → γ transformations in Fe-C-Mn-Si alloys using the NEMPF model coupled with CALPHAD database. The one-dimensional simulations of the cyclic phase transformation revealed that the switching of the polarities of Mn and Si spikes formed at the α /γ interface caused the stagnant stage where the phase transformation was suppressed. In this study, the two-dimensional simulation of cyclic phase transformation in Fe-C-Mn-Si alloy is performed using the NEMPF model in order to gain a deeper understanding of the mechanism of the stagnant stage and the transition of transformation modes.