Molecular Dynamics Studies On Liquid/Solid Interfacial Free Energy Of Undercooled Metalic Melt

The liquid/solid interfacial free energy are crucial thermodynamic parameters in determining the crystal nucleation and crystal growth during the solidification.The existence of liquid/solid interfacial free energy affects the maximum undercooling of metals during solidification,which also affects the nucleation rate and dendrite growth during solidification.However,direct experimental measurements are difficult,as the liquid/solid interfacial free energies are very small and the interface lies between liquid and solid phases.With the development of computer simulation,molecular dynamics simulation has become an important method to predict liquid/solid interfacial free energy.In this paper,the critical nucleus method is used to predict the liquid/solid interfacial free energy of a variety of pure metals and the prediction model of liquid/solid interfacial free energy change with temperature is proposed based on the results.The conclusions can be drawn as follows:1.The values of the liquid/solid interfacial energy of a variety of pure metals under certain conditions are obtained.The relation between the curvature undercooling and crystal nucleus radius is consistent with classical nucleation theory,which is the foundation on calculating liquid/solid interfacial free energy by critical nucleus method.2.In addition,the correlations between the liquid/solid interfacial free energy,melting point,melting enthalpy change and Gibbs-Thompson coefficient are studied.3.On basis of classical nucleation theory and this correlation,a thermodynamic prediction model is proposed for the change of liquid/solid interfacial free energy with temperature.