Alloying behavior and characterization of (CoCrFeNiMn)90M10 (M=Al, Hf) high-entropy materials fabricated by mechanical alloying

The alloying behavior and microstructures of the (CoCrFeNiMn)(90)M-10 (M=Al, Hf) high-entropy alloy (HEA) powders fabricated by mechanical alloying were studied. The CoCrFeNiMn)90Al10 powders have duplex solid-solution structures. In contrast, nanocrystalline HfNi3 anchoring in amorphous structures is found in the (CoCrFeNiMn)90Hf10 powders. The (CoCrFeNiMn)90Al10 powders show better ferromagnetic behaviors, mainly explained by the facilitated motion of the magnetic domain induced by the coherent interface between duplex phases. Combined with our previous work, the rules of forming solid-solution and amorphous phase in as-milled HEA powders are preliminarily proposed. It is found that, compared with the as-cast HEA reported previously, the variation range of mixing enthalpy with atomic size difference of the solid-solution formed in as-milled HEA powders is broader. Moreover, the variation ranges between mixing enthalpy and entropy with atomic size difference of the amorphous phase in HEA powder become wider than those of high-entropy bulk metallic glass.

Automated summary

This study investigates the alloying behavior and microstructures of (CoCrFeNiMn)(90)M-10 (M=Al, Hf) high-entropy alloy (HEA) powders fabricated by mechanical alloying. It is observed that (CoCrFeNiMn)90Al10 powders have duplex solid-solution structures, while (CoCrFeNiMn)90Hf10 powders contain nanocrystalline HfNi3 anchored in amorphous structures. The rules of forming solid-solution and amorphous phases in as-milled HEA powders are proposed. The as-milled HEA powders exhibit a broader range of mixing enthalpy with atomic size difference for the solid-solution formed, and wider range of mixing enthalpy and entropy with atomic size difference for the amorphous phase compared to the as-cast HEA.