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[Display omitted] • The EAM potential is suitable for characterizing the microstructure of liquid Fe-C alloy, while MEAM is not. • EAM potential could accurately predict the melting point of liquid Fe-C alloy. • Increased carbon content helps to increase the complexity of the liquid Fe-C alloy microstructure. • The transformation of Fe4C units to cementite promotes viscosity increase. The liquid Fe-C alloy is the most important system in the metallurgical process and the molecular dynamics simulation were carried out to investigate the structure and properties of liquid Fe-C alloy using EAM and MEAM potential. The local structural order, transport properties and fluidity were analyzed. By comparison, the EAM potential is better than MEAM potential to simulate the properties of liquid Fe-C system. In the liquid state, the Fe-C alloy have a short-ranged ordered structure, accompanied by the transformation of Fe 4 C units to Fe 6 C units with the carbon content increasing. And the increase in carbon content could increase the complexity of the liquid structure. In terms of transport properties and fluidity, there is an inflection point when carbon content increases to 2 wt%. When the carbon content is less than 2%, the change of Fe atom transport performance is the main factor that leads to the increase of viscosity. On the contrary, when the carbon content is more than 2%, the transportation of C atom dominates. [ABSTRACT FROM AUTHOR]

Understanding the interaction of iron and carbon is of vital importance to guide the fundamental research in the fields of metallurgy and materials science. Reaxff molecular dynamics simulation method was used to study the carburizing reaction process between graphite and molten iron. It was found that the rise of temperature can promote the carburization reaction, and the graphite prism model needs to break through a potential energy barrier when the temperature rises to 2000 K, and then carbon atoms can diffuse into the molten iron more easily. Above 2000 K, the carbon saturation of the molten iron of the graphite prism model is significantly higher than that of the graphite basal model, which proves that different carbon materials and contact ways will have different effects on the carburizing results. And it also found that high temperature can promote the mass transfer. In addition, it is found that the carburizing reaction in the graphite basal model mainly occurred in the defect parts of the graphite sheet layer. There are no defects in the graphite prism model, but the carbon atoms can be stripped from the graphite structure in the form of single atoms, diatomic carbon chains and triatomic carbon chains. [Display omitted] • The carburizing process of graphite into liquid iron was investigated from atomic scale. • The graphite different surfaces have obviously different properties. • High temperature were helpful to promote the dissolution process through making the graphite structure unstable. • Carbon atoms dissolved into the liquid iron in the form of single atoms, diatomic chains and triatomic chains. [ABSTRACT FROM AUTHOR]