Ikeda Masahiro, Aniya Masaru
Course of General Education, Natural Science, Fukui National College of Technology, Geshi-chou, Sabae, Fukui 916-8507, Japan.
Department of Physics, Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan.
Materials (Basel). 2010 Dec 10;3(12):5246-5262. doi: 10.3390/ma3125246.
The Vogel-Fulcher-Tammann (VFT) equation has been used extensively in the analysis of the experimental data of temperature dependence of the viscosity or of the relaxation time in various types of supercooled liquids including metallic glass forming materials. In this article, it is shown that our model of viscosity, the Bond Strength-Coordination Number Fluctuation (BSCNF) model, can be used as an alternative model for the VFT equation. Using the BSCNF model, it was found that when the normalized bond strength and coordination number fluctuations of the structural units are equal, the viscosity behaviors described by both become identical. From this finding, an analytical expression that connects the parameters of the BSCNF model to the ideal glass transition temperature T₀ of the VFT equation is obtained. The physical picture of the Kohlrausch-Williams-Watts relaxation function in the glass forming liquids is also discussed in terms of the cooperativity of the structural units that form the melt. An example of the application of the model is shown for metallic glass forming liquids.
沃格尔-富尔彻-塔曼（VFT）方程已被广泛用于分析包括金属玻璃形成材料在内的各种过冷液体中粘度或弛豫时间的温度依赖性实验数据。在本文中，表明我们的粘度模型，即键强度-配位数涨落（BSCNF）模型，可以用作VFT方程的替代模型。使用BSCNF模型发现，当结构单元的归一化键强度和配位数涨落相等时，两者描述的粘度行为变得相同。基于这一发现，得到了一个将BSCNF模型的参数与VFT方程的理想玻璃化转变温度T₀联系起来的解析表达式。还根据形成熔体的结构单元的协同性讨论了玻璃形成液体中科尔劳施-威廉姆斯-瓦茨弛豫函数的物理图像。给出了该模型在金属玻璃形成液体中的应用示例。
