Temperature-Dependent Configurational Entropy Calculations for Refractory High-Entropy Alloys

Abstract

AbstractThe cluster expansion formalism for alloys is used to construct surrogate models for three refractory high-entropy alloys (NbTiVZr, HfNbTaTiZr, and AlHfNbTaTiZr). These cluster expansion models are then used along with Monte Carlo methods and thermodynamic integration to calculate the configurational entropy of these refractory high-entropy alloys as a function of temperature. Many solid solution alloy design guidelines are based on the ideal entropy of mixing, which increases monotonically with $$N$$ N , the number of elements in the alloy. However, our results show that at low temperatures, the configurational entropy of these materials is largely independent of $$N$$ N , and the assumption described above only holds in the high-temperature limit. This suggests that alloy design guidelines based on the ideal entropy of mixing require further examination.