Process-Property Relationships of Light Weight High Entropy Alloys Fabricated by Physical Vapor Deposition and Bulk Synthesis

Lightweight high entropy alloys (LHEAs) represent a vast, largely unexplored space of metallic material systems with potentially revolutionary combinations of properties such as strength at high temperatures and extreme resistance to oxidation and corrosion. A first principles approach was used to predict stable compositional ranges for these alloys in the context of favorable Gibbs free energies, followed by a mesoscale approach utilizing CALPHAD and Thermo Calc. Predicted LHEA compositions were synthesized by vacuum arc melting (VAM) for proof of concept, and a high throughput physical vapor deposition (PVD) of combinatorial arrays. A systematic characterization of the synthesized thin films and bulk material was performed to derive process-property relationships. The resulting mechanical, physical, and chemical properties are used to refine computational simulations and improve properties of the subsequent iterations of synthesized alloys.