Single Phase Medium Entropy U-Based Alloys: Thermodynamics, Synthesis, and Mechanical Behavior

High and medium entropy alloys (HEAs and MEAs) exhibit superior resistance to irradiation damage: there is thus great incentive to study uranium-based HEAs and MEAs. These materials could potentially be suitable candidates for use as nuclear fuels where severe irradiation regimes prevail. In the present study, the ability to predict single phase regions in the quaternary system, Mo–Nb–U–Zr, using thermodynamic calculations was demonstrated and proven experimentally. Similarly to other known bcc HEAs systems, the bcc phase in the present MEA system was shown to exhibit high yield strength but also brittleness. It was also shown that a single phase in the MEA system, Mo–Nb–U–Zr, could be obtained only for compositions containing no more than 10 at% of Mo. Graphical abstract