Grouping strategy via d-orbit energy level to design eutectic high-entropy alloys

Recently, eutectic high-entropy alloys (EHEAs) have attracted considerable attention owing to their outstanding mechanical properties and excellent castability. However, EHEA design remains a huge challenge. Traditional grouping design strategies excessively depend on the reported alloy composition. Meanwhile, the quantitative boundary conditions of grouping strategies remain unclear. This work proposes a grouping strategy via the d-orbit energy level ( ΔMdij) to design EHEAs. The ΔMdij model was an extension of the grouping strategy, which did not require the existing alloy composition and provided a clear boundary condition for grouping the component elements. Accordingly, (CoFe2NiV0.5Mo0.2)91Zr9 EHEA with nanostructured fully eutectic morphology was designed and prepared by direct solidification. This work provided a perspective to advance the understanding of grouping design strategies for EHEAs and make it possible to design the composition of EHEAs on a large scale.