Synthesis of Al-HEA alloys by combination of mechanical alloying and spark plasma sintering

Attempts were made to synthesis Al-HEA alloys by adding high entropy alloys (HEA) to Al using the mechanical alloying (MA）-spark plasma sintering (SPS) process. CrMnFeCoNi HEA (Cantor alloy) was selected as the HEA to be added to Al, with an addition of 10 mass%. The case where Cantor alloy is added to Al (Al-10 (CrMnFeCoNi)) and the case where elemental powders of the constituent elements of Cantor alloy are added (Al-2Cr-2Mn-2Fe2Co-2Ni) are compared. Hardness and solid-state reaction were evaluated by hardness testing and X-ray diffraction. The highest hardness was exhibited 254 HV at MA16 h for Al-10 (CrMnFeCoNi) and 239 HV at MA8 h for Al-2Cr-2Mn-2Fe-2Co-2Ni, which is higher than A7075-T6 (170 HV). Compounds between Al and the constituent elements of the Cantor alloy were identified in the SPS material for each test specimen, suggesting that the main reason for the higher hardness is the compounds formed by the solid-state reaction. No significant difference in the hardness of each specimen due to the different addition methods. © 2023 The Japan Institute of Light Metals.