The liquid AlCu4TiMg alloy: thermophysical and thermodynamic properties (original) (raw)
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Thermal conductivity of liquid metals and metallic alloys
Journal of Non-Crystalline Solids, 1999
The aim of this work is to show that the electrical resistivity and the thermoelectric power can be used to determine the thermal conductivity of liquid metals and alloys. We have made this determination for liquid aluminum, tin, lead, copper and metallic alloys Cu±Al, Ag±Ga, Ag±Ge, Cu±Pb, In±Mn, Ga±Ge and Sn±Bi. For these calculations, we used the relations between the transport coecients that can be simpli®ed to the Wiedemann±Franz law. For the pure metals studied, our calculated thermal conductivities are near experimental determinations from dierent authors, showing that the Wiedemann±Franz law is valid. We predict that the Al±Cu liquid alloy has a minimum in the thermal conductivity, and in its temperature coecient versus concentration at 20 at.% of aluminum. This result is in agreement with the magnetic susceptibility data, and with the super®cial tension that have unusual magnitudes near this concentration. It is also consistent with the existence of an eutectic near the same concentration. Nevertheless, it is in contradiction with other data also deduced from resistivity measurements. We do not have any explanation of that disagreement. We show that a minimum in the thermal conductivity isotherm is also obtained for other noblepolyvalent liquid metal alloys studied, i.e. Ag±Ga and Ag±Ge. The only exception is the Cu±Pb alloy for which the calculated thermal conductivity varies monotonically with concentration. Ó
Electrical transport properties of the liquid AlCu alloys
Journal of Non-Crystalline Solids, 1990
The electrical resistivity p and the thermoelectric power S have been measured for the liquid AI-Cu alloys, from the liquidus to 1300°C, in the whole phase diagram. The resistivity isotherms show one maximum at about 25 at. % A1, which is correctly interpreted by the t-matrix formalism, in the framework of the Faber-Ziman theory. The thermopower decreases abruptly in the range of 20-40 at. % A1, when A1 is added, but this variation cannot be explained by the nearly free electron model.
Thermophysical Properties of Liquid AlTi-Based Alloys
International Journal of Thermophysics, 2010
The surface tension and density of three liquid AlTi-based alloys (AlTiV, AlTiNb, and AlTiTa) have been measured using electromagnetic levitation as a tool for containerless processing. Surface tension has been determined by the oscillating-drop method, while the density was measured using a shadowgraph technique. Both quantities were determined over a wide temperature range, including the undercooled regime. In addition, sessile-drop and pendant-drop experiments to determine the surface tension were performed in a recently built high-temperature furnace. The measured data were compared to thermodynamic calculations using phenomenological models and the Butler equation. Generally, good agreement was found.
Advanced Engineering Materials, 2020
The titanium alloy Ti–6Al–4V (Ti64) is a very widely applied alloy with extreme importance in the fields of aerospace, automotive, and biomedicine. For a large range of manufacturing methods that involve the liquid phase, such as casting, metal injection molding, thermal spraying, and additive manufacturing, process simulations are an important tool for the optimization and development of the fabrication process. Reliable thermophysical property data of Ti64 in the solid and the liquid phase are necessary inputs to such models. Due to the high melt reactivity of titanium alloys with container materials, measurements performed using conventional thermophysical equipment are usually impossible. Precise benchmark measurement of thermophysical properties (surface tension, viscosity, specific heat, total hemispherical emissivity, thermal conductivity, electrical resistivity, mass density) of Ti64 is presented in the undercooled liquid phase using containerless electromagnetic levitation ...
Thermophysical properties of some liquid binary Mg-based alloys
Journal of Mining and Metallurgy, Section B: Metallurgy, 2017
In this study, some structure-sensitive thermophysical properties, namely, electrical conductivity, thermal conductivity and thermoelectric power of liquid binary alloys Al33.3Mg66.7, Mg47.6Zn52.4 and Mg33.3Zn66.7 (all in wt.%), as the most promising cast alloys to fabricate components for cars, aircraft and other complex engineering products, were investigated. The electrical conductivity and thermoelectric power were measured in a wide temperature range by the four-point contact method. The thermal conductivity was measured by the steady-state concentric cylinder method. The obtained results are compared with literature experimental and calculated data.
2010
The variations of thermal conductivity with temperature for Al-[x] wt.% Cu, x = 3, 6, 15 and 24 alloys were measured by using a radial heat flow apparatus. The variations of electrical conductivity of solid phases versus temperature for the same alloys were determined from the Wiedemann-Franz and Smith-Palmer equations by using the measured values of thermal conductivity. From the graphs of thermal and electrical conductivity versus temperature, the thermal conductivity of the solid phases at their melting temperatures, and the thermal temperature and the electrical coefficients for the same alloys were obtained. Dependency of the thermal and electrical conductivity on the composition of Cu in the Al based AlÀCu alloys were also investigated. According to present experimental results, the thermal and electrical conductivity of Al-[x] wt.% Cu, x = 3, 6, 15 and 24 alloys linearly decrease with increasing the temperature and composition of Cu. The enthalpy of fusion and the specific heat change during the transformation for the same alloys were determined from cooling trace during the transformation from eutectic liquid to eutectic solid by means of differential scanning calorimeter (DSC).
International Journal of Thermophysics, 2007
Experimental improvements of a four-probe technique to measure the electrical resistivity of molten metals led to an improvement of the measurement uncertainty to less than 6%. Measurements of pure Al and AlSi-, AlSiMg-, and AlSiCu-alloys with a systematic variation of individual components are described. The problem of the calculation of the thermal conductivity has been investigated, and the resulting values of the binary system have been discussed in terms of behavior during melting and solidification. There is a remarkable difference of the thermal conductivity before melting and after resolidification.
Themo-Physical Properties of Al-Mg Alloy in Liquid State at Different Temperatures
Scientific Research Publishing, 2018
Thermo-physical properties of Al-Mg alloys in molten state at 1073 K have been studied using thermodynamic modeling. Thermodynamic properties, such as free energy of mixing, heat of mixing, entropy of mixing, activities and structural properties, such as concentration fluctuation in long wavelength limit, Warren-Cowely short range order parameter have been studied at 1073 K, 1173 K, 1273 K and 1373 K on the basis of regular associated solution model. The surface properties such as surface concentrations and surface tension of the liquid alloys have been studied by using Butler's model. A consistent set of model parameters have also been obtained by using optimization procedure based on statistical thermodynamics. Our analysis reveals that Al-Mg alloy is moderately interacting and it shows ordering nature at 1073 K. The nature of the alloys changes from ordering to segregating as the temperature increases.
Thermophysical Properties of Ag and Ag–Cu Liquid Alloys at 1098K to 1573K
International Journal of Thermophysics, 2010
The surface tension and density of liquid Ag and Ag-Cu alloys were measured with the sessile drop method. The sessile drop tests were carried out at temperatures from 1098 K to 1573 K, on cooling (temperature decreasing stepwise) under a protective atmosphere of high purity Ar (6N). The density of liquid Ag and Ag-Cu alloys decreases linearly with increasing temperature, and an increase in concentration of copper results in a lower density. The surface tension dependence on temperature can be described by linear equations, and the surface tension increases with increasing Cu content. The results of the measurements show good agreement with existing literature data and with thermodynamic calculations made using the Butler equation.
Surface, dynamic and structural properties of liquid Al–Ti alloys
Applied Surface Science, 2012
The systems containing highly reactive element such as Ti are the most difficult to be determined experimentally and therefore, it is often necessary to estimate the missing values by theoretical models. The thermodynamic data of the Al-Ti system are scarce, its phase diagram is still incomplete and there are very few data on the thermophysical properties of Al-Ti melts. The study on surface, dynamic and static structural properties of liquid Al-Ti alloys has been carried out within the framework of the Compound Formation Model. In spite of the experimental difficulties, the surface tension of liquid Al-2 at.%Ti alloy has been measured over a temperature range by the pinned drop method.