EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Current state-of-the-art alloys that are used for turbine or high-temperature energy applications, are usually nickel-based (super)alloys. However, the use of these alloys has fundamental limitations such as their melting temperatures, their microstructure instability under irradiation or they limited corrosion resistance. Compositionally Complex Alloys (CCAs) represent a class of alloys that have shown promising properties in extreme environments, but their development is limited by the almost limitless compositional and phase space to explore. A comprehensive high-throughput platform has been developed to design CCAs resistant to extreme environment. Additive manufacturing via directed energy deposition was employed as a high-throughput technique to synthesize hundreds of CCAs. As an example, more than 100 compositions of FeCrMnNi system were synthesized in a week, exploring a vast portion of the composition space. Tight compositional control to within ±5 at% was achieved. Alloys are further heat treated in a high-throughput fashion (50 alloys at a time) which involved homogenization, followed by aging. At each temperature, the alloys were characterized by automated EDS and XRD, SEM imaging, and microhardness. These experiments were coupled with CALPHAD modeling to expand the thermodynamic databases. Novel high-temperature gas and molten salt corrosion, and ion irradiation high-throughput testing methods were designed to test corrosion and radiation resistance of CCAs. Examples of this high-throughput platform will be presented including development of NbMoTiTaAlCr CCAs for turbine applications, FeCrMnMoNi CCAs for structural materials in high-temperature molten salt energy systems, and FeCrMnNi and light/heavy refractory CCAs for advanced fast nuclear reactors applications.