Alloy design for high-entropy alloys based on Pettifor map for binary compounds with 1:1 stoichiometry

Pettifor map for binary compounds with 1:1 stoichiometry was utilized as an alloy design for high-entropy alloys (HEAs) with exact or near equi-atomicity in multicomponent systems. Experiments started with selecting GuGd binary compound with CsCl structure from Pettifor map, followed by its extensions by selecting the binary compounds with the same CsCl structure to CuDyGdTbY equi-atomic quinary alloy and to Cu₄GdTbDyY and Ag₄GdTbDyY quinary alloys and Cu₂Ag₂GdTbDyY senary alloy in sequence. X-ray diffraction revealed that CuDyGdTbY alloy was formed into a HEA with mixture of bcc, fcc and hcp structures, whereas the Cu₂Ag₂GdTbDyY HEA was a single CsCl phase. The results suggest a potential of Pettifor map for the development of HEAs by utilizing its information of crystallographic structures. The further analysis was performed for composition diagrams of multicomponent systems corresponding to simplices in a high dimensional space. The present results revealed that a strategy of equi-mole of compounds instead of conventional equi-atomicity also works for the development of HEAs.