A Monte Carlo Simulation Study of Dissolution of Graphite in Iron-Carbon Melts

A Monte Carlo (MC) simulation study has been carried out on the dissolution of graphite in Fe-C melts in the temperature range 1300°C to 1600°C. Atoms in graphite and iron melt were arranged on a rigid graphitic hexagonal lattice and interactions were assumed to be pairwise and short ranged. This hexagonal model of iron melts has been validated using saturation solubility of C in iron melts. The aim of this study was to investigate the effect of the atomic nature of the interfacial region on graphite dissolution. Using canonical ensemble, simulations were carried out as a function of carbon content of the melt, temperature, interface orientation, and surface roughness. A contact between graphite and melt resulted in the formation of a broad interfacial region containing high concentrations of C and Fe atoms. During the initial stages of contact, strong C-C bonds in the basal plane hinder the dissociation of C atoms and affect the overall dissolution rate. As dissolution proceeds, interfacial effects become less important and dissolution is controlled by mass transfer in the melt. Interfacial effects do not play an important role across prismatic planes. The simulation results also show an excellent agreement with the basic trends in experimental results on graphite dissolution.