Study of (Ni,Cr) pre-milling for synthesis of CoFe(NiCr)Mn high entropy alloy by mechanical alloying

Cr-rich oxide is the most frequently formed on Cr-containing high entropy alloys by a powder metallurgical processing route. Therefore, in this study, the pre-milling of (Ni,Cr) elements was introduced into the CoFe(CrNi)Mn model HEAs synthesized by mechanical alloying to alter the formation behavior of Cr-rich oxides. The results suggest that the pre-milling method can promote the formation of a partial FCC solid solution phase with nanostructured Ni–Cr particles, which facilitates the nucleation of nano-Cr oxides and induces the uniform distribution of fine Cr-rich oxides dispersed in the model HEAs. Besides, the formation of Cr-rich oxides and powder agglomeration can be obstructed by the subsequent secondary ball milling.