Multiphase-Field Simulation of Cementite Precipitation during Isothermal Lower Bainitic Transformation

In the present work, isothermal lower bainitic transformation with nano-sized cementite (theta) precipitation is simulated by means of multiphase-field approach. In order to simulate the very fine cementite, ultra-small grid spacing, that is, 2nm, is applied. A faceted anisotropy model is coupled in the simulation of both bainitic ferrite (alpha(B)) and cementite (theta) growth. The simulated microstructure evolution and bainite fraction are compared with experimental results. Carbon redistribution across gamma/alpha(B) and alpha(B)/theta phase boundaries during lower bainitic transformation is further discussed.