Chemical short-range orders and the induced structural transition in high-entropy alloys

The present work verifies the existence of chemical short-range orders (CSROs) in high-entropy alloys (HEAs) using a cluster-plus-glue-atom model. Two HEAs with a composition of Al₂M₁₄ (M = Ni₄Co₄Fe₃Cr₃ or Ni₁Co₁Fe₂Cr₁) are designed, which is derived from the cluster model of [Al-M₁₂](M₂Al₁) in face-centered-cubic structure or [Al-M₁₄]Al₁ in body-centered-cubic structure. It is found that the calculated pair-distribution functions (PDFs) at short inter-atomic distances by these cluster models can describe the neutron PDFs better than the ones by the average crystal structures. It is due to the different CSROs characterized by cluster units that induce the structural transition of HEAs.