Molecular Dynamics Simulation On The Viscosity Of Liquid Metal

Firstly, we develop the program of non-equilibrium molecular dynamics (NEMD) method and apply such method to simulate the microstructure and physical properties of liquid Co. For potentials, the many-bodies interatomics potentials based on embedded atom method (EAM) proposed by Daw and Baskes have been used here. We apply NEMD approach to compute the PDF under different shear rates and viscosity values under different temperatures, and analyze the differences between simulation and experiment and the conclusions are as follows:The relations between shear rate and RDF are when shear rate is added, the layer structure still exists in the liquid state, but it becomes vague in the farther distance. We can also say that the disorder in the liquid increases.The values of viscosity obtained at the cooling rate of 5×10¹²K/s from 2000K to 1000K can be fitted to Arrhenius curves from which we can getη₀ =0.69485mPa·s, and activation energy E_a =14.94kJ/mol.Secondly, NEMD method has been adopted to simulate the micro-structure and viscosity of liquid Al based on the different potential namely Mei and Mishin for testing the accuracy in their application to the study of liquid Al. The Overlap method has been used in the paper to ensure the accuracy of viscosity. The results are as follows:Calculated pair correlation functions with Mei potential and Mishin potential are found to be very similar with the experimental value, and the relative insensitivity of the simulated liquid structures to the differences in the EAM is evident. The viscosity calculated by the two EAM potentials featured temperature dependence in qualitative agreement with experimental measurements. In particular, the Mei Potential slightly underestimates our measured result, but agreewell with the Cherne's result by Cai potential; a large discrepancy between the calculated value with our experimental value are found for the viscosity of liquid Al, where the Mishin potential overestimated our experimental result. At this stage, the present MD simulation of liquid Al illustrates that computations of structural and transport property are feasible and reliable. The values of viscosity can be fitted to Arrhenius curves from which we can get E=15.883KJ/mol, A= 0.15944mPa-s.