Microsegregation in high-entropy intermetallic compounds

High-entropy intermetallic compounds (HEICs) are a relatively new group of materials with potentially intricate properties. This work presents an experimental and theoretical study of microsegregation in single-phase (Co _0.2Cu _0.2Fe _0.2Mn _0.2Ni _0.2)Al and (Co _0.2Cu _0.2Fe _0.2Mn _0.2Ni _0.2)Zn ₃ HEICs prepared by melting technique. It is shown that the microsegregation of elements occupying the high-entropy sublattice can be explained by the nature of the constituent elements, their interaction and the characteristics of the melt crystallization. A homogenous microstructure with a γ-brass type cubic structure was obtained for (Co _0.2Cu _0.2Fe _0.2Mn _0.2Ni _0.2)Zn ₃ HEIC. Solidification with high cooling rate leads to prominent segregation in (Co _0.2Cu _0.2Fe _0.2Mn _0.2Ni _0.2 )Al, which could be highly suppressed by slow cooling from the melt state. The microsegregation behavior of the elements during high cooling rate solidification correlates with their ability to form a low-entropy intermetallic phase with the same structure as the corresponding HEIC phase. Thermodynamic and kinetic modeling could predict microsegregation in HEICs, which provide opportunities for controlling the degree of uneven distribution of elements, and consequently, the properties of the resulting material using heat treatment.