Preparation of superfine-grained high entropy alloy by spark plasma sintering gas atomized powder

• Nanocrystalline CrMnFeCoNi HEAs can be prepared by powder metallurgy (PM) method.
• The PM HEAs have a high tensile strength and a suitable ductility.
• The original morphology and defects in the powders can be inherited to the bulk materials.

In this work, nanocrystalline CrMnFeCoNi HEAs were prepared by powder metallurgy. It was found mechanical milling can further refine the microstructures and morphologies of the gas-atomized powder, and increase the sintering ability. The HEAs sintered from the mechanically milled powder have much finer microstructures than that from the gas-atomized powder. The original morphology and defects in both the gas-atomized and the mechanically milled powders can be inherited to the bulk forms after the SPS. The SPSed HEAs have a tensile strength as high as 1000 MPa at room temperature and reasonable ductility. The strengthening mechanism can be attributed to the nanocrystalline microstructures, in which grain boundaries block the movement of dislocations. Powder metallurgy can be taken as a promising way for preparing HEAs with high mechanical properties.