Department of Mechanical and Materials Engineering, Nicol Hall, Queen's University, Kingston, ON K7L 3N6, Canada.
J Phys Condens Matter. 2010 Jan 27;22(3):035105. doi: 10.1088/0953-8984/22/3/035105. Epub 2009 Dec 24.
The identification of the manner in which a solute diffusion coefficient (D) might vary with temperature (T) in a fused metal or semimetal has led to considerable experimental study and some theoretical analysis. However, the conclusions of this work are inconsistent. In the present work, molecular dynamics studies of diffusion of a very dilute solute (Au) in liquid Cu are presented. Using the simple Enskog theory of diffusion, it is shown that the ratio of the diffusion constant of the solute to the diffusion constant of the solvent for a very dilute solution is approximately constant. This prediction is confirmed by molecular dynamics simulations although the values of ratios agree only within 20%-25%. In agreement with experiment, current simulations predict that within the usually investigated temperature range, the diffusion coefficient is linearly dependent on temperature. A very small contribution of parabolic behavior can only be observed for a temperature range much wider than that available for physical experiments due to materials limitations.
溶质扩散系数（D）随熔融金属或半金属温度（T）变化方式的确定，导致了大量的实验研究和一些理论分析。然而，这项工作的结论并不一致。在本工作中，我们提出了在液态 Cu 中非常稀溶质（Au）扩散的分子动力学研究。利用扩散的简单 Enskog 理论，表明非常稀溶液中溶质扩散常数与溶剂扩散常数的比值近似为常数。虽然比值的数值仅在 20%-25%内一致，但分子动力学模拟证实了这一预测。与实验一致，目前的模拟预测，在通常研究的温度范围内，扩散系数与温度呈线性关系。由于材料限制，只有在比物理实验可用的温度范围宽得多的温度范围内，才能观察到抛物线行为的很小贡献。
