Liquid-phase separation of immiscible CrCuxFeMoyNi high-entropy alloys

摘要

Taking into consideration the large positive mixing enthalpy of Cu-Mo, in this work, the relative content of Cu and Mo elements was adjusted to investigate the solidification process and microstructure formation of CrCuxFeMoyNi high-entropy alloys. For CrCu0.5FeMoyNi (y = 0.5, 1) high-entropy alloys, many Cu-rich spheres were observed in the as-solidified microstructures, while macroscopic phase separation structures were obtained in CrCuFeMoyNi (y = 0.5, 1) alloys. Liquid-phase separation occurred in high-entropy alloys when the enthalpy of mixing (Delta H-mix)was positive, the valence electron concentration (VEC) was in a range of 8.09-8.44 and the difference in atomic radii (delta) was between 3.39 and 4.25. For lower positive Delta H-mix, Cu-rich spheres were observed, while for higher positive Delta H-mix, macroscopic phase-separated structures were obtained.