简单熔体粘滞系数的普适性标度关系

THE SCALING LAW FOR VISCOSITY COEFFICIENTS OF SIMPLE MELTS

运用分子动力学方法,对一系列简单熔体(包括Ag,Al,Au,Co,Cu,Mg,Ni,Pb,Pd,Pt,Rh和Si)的粘滞系数和过剩熵之间的标度关系进行了深入的研究．计算结果证实了Rosenfeld的粘滞系数标度关系,应用Dzugutov的方法定义了一个新的约化牯滞系数,并根据大量的模拟数据拟合出了一个新的粘滞系数标度关系．分析了在简单熔体中存在牯滞系数与过剩熵普适标度关系的物理本质,同时明确论证了标度关系与Arrhenius关系之间的密切联系,即过剩熵与温度的倒数存在正比关系．

Employing a realistic many-body potentials for a series of simple melts, including Ag, Al, Au, Co, Cu, Mg, Ni, Pb, Pd, Pt, Rh and Si, and using the molecular-dynamics simulation the scaling laws of viscosity with different expressions of the reduction parameters were studied. The simulated results support the universal scaling laws proposed by Rosenfeld for transport coefficients in liquid metals. Following Dzugutov＇s method, a universal scaling relationship between the viscosity coefficient and excess entropy was obtained. In particular, it is found that there exists a link between the scaling law and the Arrhenius law, i.e., the excess entropy scaling law for the viscosity coefficient can be interpreted as a straightforward extension of the Arrhenius law.