Modeling of the Divorced Eutectic Solidification of Spheroidal Graphite Cast Iron
The solidification of the austenite-spheroidal graphite (SG) eutectic is one of the most complex and therefore most difficult liquid-to-solid transformations to describe through computational modeling. This is because the iron-carbon equilibrium phase diagram is an asymmetric diagram that predicts that at relatively low solidification velocities it is possible to produce primary austenite in a casting of eutectic composition. In addition, the two phases of the eutectic solidify as a divorced eutectic, with only the austenite being in contact with the eutectic liquid. The paper proposes a computational model for the eutectic solidification of SG iron with visualization of the microstructure evolution using a cellular automaton technique. The model is an extension of the earlier Zhu-Stefanescu model for primary phase solidification and includes the growth of primary SG in the liquid, of primary austenite and of the austenite-graphite eutectic controlled by carbon diffusion through the solid austenite shell. The model outputs realistic images of the microstructure evolution from the beginning to the end of eutectic solidification of SG cast iron.
Adel Nofal and Mohamed Waly
H. L. Zhao et al., "Modeling of the Divorced Eutectic Solidification of Spheroidal Graphite Cast Iron", Key Engineering Materials, Vol. 457, pp. 324-329, 2011