液态结构与性质关系Ⅲ——剩余键理论模型

Relationship between liquid structure and property Ⅲ——residual bond theoretical model

利用剩余键的思想,通过数学推导,建立定量描述金属熔体结构与黏度关系的物理模型,提出黏度的微观结构变化特性为熔体剩余键结构尺寸d的演变;应用建立的模型理论计算液相线以上一定温区镁熔体和铝熔体的运动黏度,得到函数关系式分别为υ_(Mg)=3.17×10^(-7)+3.04×10^(-7)·d和υ_(Al)=1.65×10^(-7)+1.05×10^(-7)·d,这与采用坩埚扭摆振动法的实验测量结果相符合.该模型从化学结合键角度揭示了金属熔体的结构微观不均匀性及其黏度的微观物理本质,为金属熔体黏度的理论计算提供了一种新的途径.这对于深入认识液态金属的微观结构及其与宏观物性之间的关系具有重要意义.

Based on the concept of residual bond, a physical model quantitatively describing the relationship between the melt structure and viscosity of metal is established by mathematical deduction, and the microscopic nature of viscosity is considered to be the evolution of the size d of the residual-bond structure of melt. Using this model, the kinematic viscosityies of the magnesium and aluminum melt in a certain region above the melting point are calculated, and the functional relations VMg = 3.17 X 10-7 ＋ 3.04 X 10-7 ~ d and vAl = 1.65 x 10-7 ＋ 1.05 x 10-7 ~ d are obtained, which accord with the experimental data measured by the method of crucible rotating oscillation damping. This model reveals the microscopic naturs of the micro-inhomogeneity and viscosity of the melt structure from the view of chemical bond, which provides a new way to calculate the viscosity of melt and is of significance for understanding the relationship between microstructure and macroscopic properties of liquid metal.