Synthesis and Characterization of Nanocrystalline High Entropy Heusler Intermetallics Powders

This study demonstrates the possibility of bringing novel Full Heusler high-entropy intermetallic compounds (FH-HEICs) to nanoscale regime. To this end, Co₂(FeNiMnMgZn)Al, Co₂(TiZrTaNbCr)Al and Cr₂(TiZrTaNbV)(AlSi) FH-HEICs are prepared by mechanical alloying for 20 h. All FH-HEICs crystallize in a mixture of partially ordered B2-type and disordered A2-type crystal structures, which exhibit higher degree of disordering compared to the ideal L2₁ structure. Scanning electron microscope micrographs and Energy dispersive spectroscopy mapping confirm the homogenous distribution of elements within the nanocrystalline particles. Co₂(FeNiMnMgZn)Al and Co₂(TiZrTaNbCr)Al exhibited semi hard magnetic behavior with magnetic saturation of 50.93 emu/g and 18.73 emu/g at 300 K, respectively. Cr₂(TiZrTaNbV)(AlSi) exhibited hard magnetic behavior with giant coercivity of 3.5 kOe and low magnetic saturation of about 0.2 emu/g. Finally, we introduce FH-HEICs as a novel group of functional materials with potentially intricate magnetic and catalytic properties, in which the order-disorder transition and wide chemical composition range provide unprecedented opportunity to tune their structural and functional properties.