Density, Viscosity, and Electrical Conductivity of Hypoeutectic Al-Cu Liquid Alloys
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INTRODUCTION
THERE is a continual demand to optimize methods and facilities for material processing technologies such as melting, refining, or casting of metallic alloys. The main goals are an improvement of the final product quality, an enhancement of the process efficiency, and an economical consumption of resources and energy. Nowadays it is impossible to imagine such optimization without performing numerical simulations and a corresponding physical modeling. However, the accuracy of the predictions depends sensitively on the availability of precise and trustworthy data concerning the thermophysical properties of the alloys under consideration. The development of new workable aluminum-based light alloys is a key issue in current materials science. Al-Cu alloys, for instance, AlCu4TiMg, are the most used casting alloys in the aluminum industry. The distinctive characteristics of these alloys are low density, high melting temperature, good thermal conductivity, and excellent oxidation resistance. Al-Cu alloys are ubiquitous in technical applications: they are the main components for screw machine products, truck frames, aircraft structures, jet engine impellers, and aircraft engine cylinder heads. Moreover, binary Al-Cu alloys are the focus of numerous, academic studies, which are especially concerned with solidification processes and consider, for instance, the columnar-to-equiaxed transition,[1–3] the formation of macrosegregation zones,[4,5] the visualization of the dendritic growth,[6,7] the impact of melt convection,[8–10] and the application of electromagnetic Y. PLEVACHUK and V. SKLYARCHUK, Senior Research Scientists, and A. YAKYMOVYCH, Junior Research Fellow, are with the Department of Metal Physics, Ivan Franko National University, 79005 Lviv, Ukraine. S. ECKERT, Group Leader, and B. WILLERS, Senior Research Scientist, are with the MHD Department, Forschungszentrum Dresden-Rossendorf, 01314 Dresden, Germany. Contact e-mail: [email protected] K. EIGENFELD, Professor, is with the Foundry Institute, TU Bergakademie Freiberg, 09599 Freiberg, Germany. Manuscript submitted January 18, 2008. Article published online October 15, 2008 3040—VOLUME 39A, DECEMBER 2008
stirring.[11,12] The solidification process of a liquid alloy has a profound impact on the structure and properties of the solid material. Therefore, the knowledge of the physical properties of the molten alloys prior to solidification becomes very important for the development of materials with predetermined characteristics. Among all physical properties, the structure-sensitive characteristics of the liquid phase play a prominent role. The density is directly related to the atomic structure and potential short-range order of the liquid. On the other hand, it is a fundamental quantity for all technological applications, because it determines fundamental nondimensional parameters characterizing fluid flow, such as the Reynolds or the Rayleigh number. Reliable information about the structural heterogeneity[13] of the melt can also be obtained from studies cons
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