A comparison of the molecular interaction volume model with the subregular solution model in multicomponent liquid alloy
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1/8/04
7:49 PM
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A Comparison of the Molecular Interaction Volume Model with the Subregular Solution Model in Multicomponent Liquid Alloys DONG PING TAO The molecular interaction volume model (MIVM) is a two-parameter model, meaning it can predict the thermodynamic properties in a multicomponent liquid alloy system using only the coordination numbers calculated from the ordinary physical quantities of pure liquid metals and the related binary infinite dilute activity coefficients, gi and gj, which avoids somewhat adjustable fitting for the binary parameters of Bji and Bij. In comparison with the subregular solution model (SRSM), the prediction effect of the MIVM is of better stability and safety because it has a good physical basis.
I. INTRODUCTION
SOLUTIONS thermodynamics is one of the fundamental theories of materials science and engineering because the preparation, development, and design for a variety of materials, such as metal alloys, porcelain and ceramics, plastics, as well as their reunited materials, have needed to provide thermodynamic properties at certain environmental conditions. Therefore, over 100 years, the research in the realm of solutions thermodynamics has been never interrupted, and will continue to probe deeply into the essence of its subject matter. For the sake of clearly arguing for the meaning of this work, it is necessary to classify relevantly those models of solutions thermodynamics that relate to liquid alloy systems. The main classifications that have been suggested are as follows. Ansara’s classification:[1] The interaction models or statistical models and empirical equations. The former includes the regular solution model, quasi-chemical approximation, and central atom model, which emphasize the configuration of solution atoms and the types of bonding energies; the latter includes the Wohl formula, Margules equation, Scatcard–Hamer equation, Krupkowski equation, Wilson equation, Bonnier equation, Toop equation, Kohler equation, and Colinet equation, which emphasize interpolation of the multicomponent data from binary experiment data. Hillert’s classification:[2] physical models and mathematical models. The former has the prior consideration of physical meaning, and the latter has to consider the actual application. Hillert emphasized that the sounder the physical model underlying a mathematical model, the safer its predictions will be. In order to make predictions far away from the experimental data point, i.e., in order to extrapolate the experimental information, one needs a model with a good physical basis. Zhou (Chou)’s classification:[3] physical models and numerical models. The former based on the matter structure predicts the thermodynamic properties of melts from the principles of quantum mechanics and statistical mechanics. Its advantage is DONG PING TAO, Professor, is with the Faculty of Materials and Metallurgical Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan Province, People’s Republic of China. Contact e-mail: dongpingt
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