Structure and property of metal melt III—Relationship between kinematic viscosity and size of atomic clusters

Abstract

The method of crucible rotating oscillation damping was employed to measure the kinematic viscosity of aluminum melt, and the curve of viscosity v versus temperature T from 935 to 1383 K was obtained. Besides, based on the calculation model of the evolution behavior of atomic clusters in liquid structure, the curve of atomic clusters size d versus temperature was obtained, and the calculated results are in good agreement with the experimental values. By analyzing experimental data, it was found that both the viscosity and the size of atomic clusters of aluminum melt are monodrome functions of temperature, and the relation between v(T) and d(T) is a linear function, i.e., v = v 0 + K·d(T). This relation indirectly verifies the calculation model of the structural information of metal melt, which is of great significance for studying the relation between melt microstructure and macro-physical properties. kinematic viscosity, atomic cluster, linear relation, melt structural information, model validation PACS: 62.10.+s, 83.85.Jn, 61.25.-f, 61.25.Mv, 61.20.GyAs a kind of primary state of matter, the liquid state has its own special structure and physical properties compared with the solid and gaseous states. In addition, the liquid state is the origin of crystalline and some non-crystalline materials. So it is very important to investigate liquid, especially the high temperature melts [1]. However, the research on the structures, properties and evolution behaviors of liquid is far not enough [2].Since the formula for calculating the viscosity of liquid was deduced according to the radial distribution function and atomic interaction potential, study of the relationship between microstructure and viscosity of liquid metal has been always an important and difficult task in condensed matter physics [3,4]. In the past 60 years, the properties and nature of viscosity were intensively researched, and many theoretical models and empirical formulas were proposed to describe the relationship between viscosity and temperature, viscosity and melt structure [5][6][7][8][9], such as the Born-Green formula built on the distribution function, the Frenkel model based on the cavity theory, the Iida correction model of the Andrade relationship deduced by the Lindemann melting laws and so on, those laid a good foundation for the knowledge of the microstructure of melt through the variation law of viscosity. However, due to the complexity of the microstructure of metal melt and the instability of the measurement of viscosity, the relationship between viscosity and melt structure is still not very clear, and the existing models or formulas cannot directly reflect the simple relationship between them. In this paper we will give a further description on this relationship based on the theory of micro-inhomogeneity of liquid metal.In the authors' previous work, the calculation model for structure information of metal melt was obtained through

The effect of superheat on the nucleation undercooling of metallic melts

“…Based on these studies, the grain refinement is prohibited in light of the partial remelting of the preferential nuclei and nucleus clusters during the superheating treatments applied on the melts. 17 Iglev and Luo 18,19 found defect-free ice that can be superheated by experiments and simulation due to the complex threedimensional network of hydrogen bonds that holds water molecules together. Forsblom et al 20 revealed that the melting of aluminum initiated by thermal fluctuation aggregated with typical six to seven interstitials and three to four vacancies using atomistic simulations, instead of involving more extra populations of atoms at the initial stage of melting.…”