Thermophysical Properties of Liquid Metals and Alloys

The thermophysical properties of liquid metals and their alloys encompass key parameters such as density, surface tension, viscosity, electrical resistivity, thermal conductivity, thermal diffusivity and specific heat capacity. These characteristics govern the behaviour of melts during casting, welding, additive manufacturing and high-temperature energy applications. Density and volumetric thermal expansion inform flow patterns and buoyancy-driven convection, while surface tension influences droplet formation, wetting and capillary phenomena in micro- and nano-scale processes. Viscosity controls shear flow and solidification kinetics, and electrical resistivity underpins joule heating during inductive processing. Thermal conductivity and diffusivity determine heat transport within the melt, impacting solidification morphology and thermal stress development. Specific heat capacity dictates the energy required to raise melt temperature and thus the response to rapid heating techniques. Measurement of these properties often relies on containerless methods—electromagnetic or electrostatic levitation—and on high-rate ohmic pulse-heating to avoid contamination and nucleation effects. Complementary modelling approaches, from empirical correlations to thermodynamically self-consistent formulations, enable interpolation and prediction across temperature and composition ranges. Together, experimental advances and predictive frameworks have broadened understanding of liquid metal behaviour, facilitating optimisation of industrial processes and the design of novel high-performance alloys with tailored melt characteristics.

Research from Nature Portfolio

Recent studies have established a unified formalism linking temperature and oxygen adsorption to the surface tension of liquid metals, demonstrating that explicit control of impurity levels is essential for predictive modelling in applications ranging from nanofabrication to molten-salt reactors. This approach yields reliable expressions for both pure and oxygen-saturated metals, with aluminium serving as a detailed case study. Another work has extended geometric and thermodynamic models to quaternary Sn-Ag-Cu-Bi alloys, evaluating surface tension, molar volume, density and viscosity across a broad compositional and thermal window. By adapting classical mixing and Guggenheim formulations, these models deliver accurate estimates in good agreement with experimental data, offering a powerful toolkit for alloy design in electronics soldering and lead-free interconnects.

Thermophysical Properties of Liquid Metals and Alloys publication trend

The graph below shows the total number of articles in thermophysical properties of liquid metals and alloys across all publications each year (not limited to Nature Index journals).

Technical terms

Surface tension: Free energy per unit area at a liquid–gas interface, governing droplet shape and wetting.

Viscosity: Resistance of a fluid to shear or flow, influencing melt stirring and solidification rates.

Electromagnetic levitation: Containerless technique using alternating magnetic fields to suspend and heat conductive melts.

Ohmic pulse-heating: Rapid resistive heating via high-current pulses to reach liquid temperatures within microseconds.

Thermal diffusivity: Ratio of thermal conductivity to volumetric heat capacity, indicating the speed of temperature equalisation.

Specific heat capacity: Energy required to raise the temperature of a unit mass by one degree, determining thermal inertia.

References

1. Thermophysical Properties of Liquid Aluminum. Metallurgical and Materials Transactions A (2017).
2. Temperature and oxygen adsorption coupling effects upon the surface tension of liquid metals. Scientific Reports (2019).
3. Temperature dependences of surface tension, density and viscosity study of Sn-Ag-Cu with Bi additions using theoretical models. Scientific Reports (2019).
4. Effect of Boron Micro-alloying on the Surface Tension of Liquid Iron and Steel Alloys. International Journal of Thermophysics (2020).
5. Uncertainty analysis and performance evaluation of thermophysical property measurement of liquid Au in microgravity. npj Microgravity (2023).