Elemental segregation in solid-solution high-entropy alloys: Experiments and modeling

Recent experiments showed that elemental segregation occurs in some high entropy alloys (HEAs) although their X-ray diffraction patterns exhibit a nominal single-phase solid solution structure. Based on the 3-D atom probe tomography (APT) results obtained from the FeNiCoCrCu HEA, here we propose a simple thermodynamics model based on the notion that elemental segregation facilitates stabilizing the solid solution phase with a minimized Gibbs free energy. Our model enables distinguishing nominal single-phased solid-solution HEAs with and without elemental segregation. The predictions of our model are found in good agreement with the experimental data reported hitherto in the literature.