ABSTRACT
A reference-free modified embedded atom method (RF-MEAM) potential for iron has been constructed. The new potential is made to predict both bcc and fcc (α-Fe andγ-Fe) lattice properties, with a special interest in modelling in the 800-1300 K temperature range. This is the range in which transformations and key processes in steel occur. RF-MEAM potentials can be used directly in commonly used molecular dynamics simulation software (e.g. LAMMPS). The new potential is compared to several other (M)EAM potentials which are commonly used. It is demonstrated that the new potential combines good characteristics for point defect energies with free surface and stacking fault energies. Also the Nishiyama-Wassermann and Kurdjumov-Sachs orientation relation ratios and interface energies are reproduced, allowing for simulations ofα-Fe andγ-Fe interphases.
ABSTRACT
A fast three-dimensional phase transformation model is formulated for the transformation from ferrite to austenite in low-carbon steel. The model addresses the parent microstructure, the nucleation behaviour of the new phase and the growth of the new phase. During the growth, the interface velocity of the ferrite grains is calculated using a mixed-mode growth model. The simulated transformation kinetics is compared with experimental kinetics for an Fe-C-Mn steel for four different cooling rates. In general, the model predicts the kinetics quite well. In addition, the mixed-mode character of the transformation is shown for the different cooling rates.
