ISSN 0018-151X, High Temperature, 2014, Vol. 52, No. 3, pp. 386–390. © Pleiades Publishing, Ltd., 2014. 386 1 INTRODUCTION Pure liquid metals have been studied since many decades and their fundamental properties may be con- sidered on a firm basis (e.g. [1]) especially due to the studies conducted the ‘60 and the ’70 by such authors as Grosse (1961), Ziman (1961), Edwards (1962), Allen (1963), Faber (1966), Ashcroft (1966), Ascarelli (1969), Lang (1970), and Filippov (1966) (see [1] for more details). However, the same is not true for alloys which are still under investigation. In the last years, there have been investigations of some alloys, such as Al–Cu, Pb–Bi and Pb–Sn [2], but the experimental data are sometimes contradictory. This work aims at providing a method for estimating the main physical properties at standard pressure (i.e. one atmosphere) to describe metal alloys in the liquid state in order to offer a reliable approximated approach. Density, sur- face tension, electrical resistivity and, consequently, thermal conductivity are the considered values. Given these literature data (i.e. [3–9]), we choose to test the model on the Al–Cu and Al–Si systems. These alloys have been investigated during the recent years with the most qualified experimental methods and the data obtained seem to be consistent. DENSITY Density is important because it determines the mass flow and influences the heat transfer [10]. It also determines the solidification transformation [11]. In the model we previously proposed [12], it was shown that density influences the relationship between vis- cosity and temperature. 1 The article is published in the original. On the one hand, the density of an alloy may be determined only experimentally because the models proposed in literature are inadequate to satisfy the industrial needs which often involve complex chemi- cal compositions. On the other hand, the knowledge of this property is essential for simulating and setting the design of every metallurgical process. Here, a new model is presented for estimating the density of a binary alloy and it is compared with the most recent assessed data. We begin by considering the alloy as an ideal solu- tion of two elements A and B. Under this hypothesis the alloy is studied as an ideal mixture of gases, where the properties of the AB solution are determined by the sum of the fraction ρ AB, of the alloying elements. According to this model we consider the density of the alloy under ideal condition ρ AB,id to be expressed with the “linear mixture rule” as: (1) where ρ A , ρ B are the density of pure metals A and B, X A and X B are the components mass fraction of each pure element for which this property is valid Now, we compare the ideal properties with the experimental values. Given the importance for indus- tries and the availability of experimental data in litera- ture we choose to conduct the investigation under two well-tested systems: Al–Cu and Al–Si. By an empirical examination one may observe that along the liquidus line this proportion holds: (2) where and T L are the density and the temperature of the alloy along the liquidus line. Using an ideal mix- ing ratio, the melting temperature of the alloy T* is , , AB A A B B X X ρ = ρ + ρ id 1. A B X X + = 1 , , AB L AB T T ρ = ρ id * AB ρ 1 Empirical Model for the Estimation of Thermophysical Properties of Liquid Metal Alloys 1 D. Ceotto a and F. Miani b a DIEGM—Universitá degli Studi di Udine b DICA—Universit@a degli Studi di Udine 33100 Udine (Italy) e-mail: diego.ceotto@uniud.it Received July 19, 2013 Abstract—A model for calculating the main properties of liquid metal binary alloys at standard pressure based on experimental data observation is presented. Given the characteristics of the pure metals, the model allows to calculate density, surface tension, electrical resistivity and thermal conductivity of binary alloys at various concentrations along the liquidus line. Some preliminary comparisons for Al–Si and Al–Cu systems are in satisfactory agreement with the model. DOI: 10.1134/S0018151X14030249 1 THERMOPHYSICAL PROPERTIES OF MATERIALS