The relationship between inter-diffusion and self-diffusion of different liquid metals studied by molecular dynamics simulations

摘要

Long-capillary simulation method was used to calculate the inter-diffusion coefficient using nonequilibrium molecular dynamics simulations. The inter-diffusion coefficient of the binary Al80Ni20, Al80Cu20, La80Ni20 and La80Al20 melts were calculated over a wide temperature range. We found that the relationship between inter-and self-diffusion coefficients of Al80Cu20 melts can be well expressed by Darken equation, which agreed with the previous results. For Al80Ni20, La80Ni20 and La80Al20 melts, dynamic cross correlation factor S was needed to correlate the Darken equation. S of Al(80)Ni(20)and La80Ni20 ranged from 0.68 to 0.92, while that of La80Al20 was larger than 1. The effect of pressure on S was further investigated. We found that S of Al80Ni20 under 30 GPa was about 0.46 at 2000K and it was much lower than that of zero pressure, which means that the pressure had a great influence on S. Our investigations provided an improved understanding of cross correlation factor S.

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