Liquid metal characterization by levitation at high pressure and high temperature – CaraMeLL

To achieve its objectives, the project relies on two complementary pillars: numerical modeling and experimentation.

On one hand, advanced computer models will be developed to reproduce the behavior of liquid metals in the levitation system. These models will simulate heat transfer, liquid metal flow, chemical element diffusion, and even evaporation, to predict what happens inside the experiments. This helps design more effective experiments and understand physical phenomena beyond what cameras or instruments can directly observe.

In parallel, a unique experimental setup will be built to levitate a small droplet of liquid metal without any contact while increasing the surrounding pressure. This approach offers two main advantages:

It avoids contamination from a container thanks to levitation,

It prevents the metal from evaporating too quickly, which typically limits achievable temperatures in other laboratories.

With this approach, it will be possible to measure essential properties of liquid metals, such as density, surface tension, and heat capacity, at temperatures never reached before.

A complete experimental platform capable of characterizing the thermophysical properties of liquid metals up to 4,000 °C, under high pressure, with fine control of stability and environmental parameters. [Progress: 4/5]

Novel data on density, heat capacity, and surface tension for strategic metals and alloys (iron, nickel, titanium, zirconium, stainless steels, superalloys). [Progress: 2/5]

In-depth understanding of evaporation phenomena and the effect of pressure, through the integration of numerical modeling and experimental measurements. [Progress: 3/5]

Open-source communication of thermophysical properties for the scientific and industrial communities, with the possibility of extending to other materials. [Progress: 0/5]

Methodological advances in high-temperature and high-pressure measurements, exportable to other laboratories and industries. [Progress: 2/5]

Direct industrial impact on welding defect prediction, new alloy design, and optimization of additive manufacturing and fusion processes.

While the core of the project is the creation of a one-of-a-kind experimental system, the main perspectives involve extending the measurements to other complex materials: stainless steels, metallic glasses, superalloys. Wherever the evaporation of one or more alloy elements poses a problem, the continuation of the project could prove beneficial.

In the future, it will thus be possible to characterize various types of complex liquid alloys particularly sensitive to evaporation. The system will enable the measurement of density, heat capacity, or surface (and Marangoni) tensions over a temperature range from 1,000 °C to 4,000 °C.

All studies of material properties within this range are conceivable.

The partial knowledge of the physical properties of metals in liquid state is today a lack in the understanding of physical phenomena and a key issue for the development of multiphysics models. This information, very difficult to access, is required in many sectors: automotive, aerospace, naval, energy, wherever metal alloys are strongly used. Unfortunately, the current literature is incomplete or temperature limited.
For example, metal additive manufacturing makes it possible to create parts by depositing exclusively molten metal. The development of this technology is based on thermo-hydrodynamic modelling and experimental research, both requiring extensive knowledge of the thermophysical properties of molten metal in order to understand the appearance of defects and analyse the observed physical phenomena (example : Marangoni)..
The CarameLL project aims to establish a breakthrough in the measurement of thermophysical properties of molten metals by using a non-contact aerodynamic levitation device allowing high temperature measurements of surface tension, viscosity or specific heat of molten metals. This method, rather well known and already used at IRDL, will be coupled, for the first time in the CarameLL project, with a new methodology consisting in measuring under very high pressure in order to reduce as much as possible the phenomena of evaporation of alloying elements and of base metal. This idea will make it possible to reach much higher temperatures and to keep intact the chemical composition of alloys characterized. It will also make it possible to study more fundamentally the evaporation of alloying elements. Another originality, the project will be based on multiphysics modeling allowing the lifting of the last locks.