HEA solutions for light armouring: from predictive metallurgy to manufacturing optimised parts – SHIELD

The SHIELD proposal aims to introduce an alternative to some armor steels, based on High Entropy Alloys (HEAs)/Complex Concentrated Alloys (CCAs). These metallic alloys have been discovered in the mid 2000’s and have since been the subject of intensive studies. They indeed exhibit interesting, and sometimes surprising, properties, and particularly mechanical properties. The first generation of HEAs was developed on the ground base of obtaining a single disordered solid solution. However, recent development was mostly focused on generating complex yet controlled microstructures bearing a disordered solid solution and a strengthening phase.
Currently, light armoring is provided by a specific family of low alloy steels, whose specific gravity values are rather high. Based on a HEAs/CCAs development strategy, the goal of this project is to design, manufacture and characterize a low mass density alloy exhibiting mechanical properties at least, as elevated as the existing armor steels. Consequently, in terms of specific properties the alloy solution candidate is expected to minimize the mass of the armored vehicles.
Our approach is composed of five work packages, organized into two phases.
The first work package will consist in predictive thermodynamic calculations in order to propose several candidate alloys, that have the potential to fulfill the project requirements (mainly mechanical properties such as hardness, strength and ductility).
The second work package will allow, inside the boundaries of the first project phase, to manufacture these candidate alloys by a fusion/solidification route followed by an appropriate thermomechanical treatment. The manufactured alloys will then be thoroughly characterized in terms of microstructure and functional properties (mechanical properties and corrosion resistance) within the framework of two transverse work packages. As a matter of fact, the first project phase will lead to the selection of the most two promising alloys among the candidates, which will thus be manufactured by a powder metallurgy route. We believe this route will generate finer microstructures and consequent enhanced properties, since processes like Spark Plasma Sintering (SPS) will be used.
In order to achieve this project, the consortium is composed of ICMPE (UMR7182) and LSPM (UPR3407). The two labs collaborate on the specific subject of high entropy alloys since 2012. They have published in common many scientific works. They possess extensive experience in all theoretical and experimental tasks that are developed within the SHIELD proposal.