Predicting the Density of Solid and Liquid Near-Eutectic Ga–In–Sn Alloy

Europe has set itself the goal of reducing net greenhouse gas emissions to zero by 2050. This requires innovative concepts for the transfer of thermal energy. One of these could be the use of liquid metals and alloys as heat carriers. For this purpose, the precise knowledge of the thermophysical properties of these materials is of great importance. This study therefore aims to model the temperature dependent density of solid and liquid near-eutectic gallium-indium-tin alloys. Three approaches—weighted fitting of experimental data, modelling based on atomic volumes of alloying elements, and an approach that accounts for possible excess density—are utilised. Details of these strategies with respect to the thermophysical properties of the alloying elements, and the binary sub-alloys, are discussed. The resulting correlations are validated using six independent experimental data sets. The study concludes that, currently, the fitting polynomials are the most reliable models. The estimates based on atomic volumes are in close agreement with these functions. This is true for both the solid and liquid states. This marks the first time that the density of the solid state of this particular alloy has been modelled. The difficulties associated with modelling the density excess are manifold. This includes the lack of precise thermophysical properties for the alloying elements. The study paves the way for near-eutectic liquid gallium-indium-tin alloy as a heat carrier. In the view of the potential importance of heat transfer employing liquid metals, these findings highlight the need for further investigations in this field.