Design of Eutectic High Entropy Alloys

Eutectic high entropy alloys (EHEAs) are emerging as an exciting new class of structural alloys as they have shown promising mechanical properties. However, how to design these alloys has been a challenge. In this work, a thermodynamic approach based on the phase rule is developed for designing EHEAs. Furthermore, the ideas of compositional phase diagrams and mixing eutectic alloys are introduced, and it is shown how these methods could be used for designing new EHEAs. The approach is applied for alloy systems Al–Co–Cr–Fe–Ni and Co–Cr–Fe–Ni–Ti, and several EHEAs are predicted for these alloy systems. The predicted results are verified with thermodynamic simulations and experimental data. The results show that the introduced approach can be considered as a feasible and easy-to-use method for designing EHEAs. Based on the developed approach, a procedure is provided in this work for designing EHEAs which can be applied for any binary or ternary eutectic system.