Comparison of solidification behavior between in situ observation and simulation of Fe-C-Si system

Over the last few years, important advances have been made in the understanding and modelling of phase transformations of metallic alloys including (a) the coupling of phase equilibria and kinetics for computerised simulation of multicomponent alloys and (b) in situ time resolved X-ray imaging of phase transformations in real time. Both techniques can be complementary. However the quality of the simulation relies to a large extent on the accuracy of phase equilibria and diffusion data obtained from existing experimental studies. In situ X-ray techniques provide quantitative information on the evolution and proportion of phases, and can validate the thermodynamic/kinetic packages. This validation in-turn improves the computational models and databases. In the present work, the phase transformation in the Fe-C-Si system from liquid to γ-Fe and the reaction liquid ↔ γ-Fe + Cementite was observed by using X-ray imaging at SPring-8 synchrotron. The relationship between fraction solid and temperature was obtained from the generated SPring-8 images. The results are compared with computer simulation using Thermo-Calc. and DICTRA. A critical analysis compares the results of the simulation with the real-time observations of the phase transformation.