Local Chemical Environments in Magnetic High Entropy Alloys*

Chemical and magnetic ordering in the body-centered cubic high entropy alloy FeCoCrNiAl₂ was investigated. Characterization and parametrization of chemical ordering in this and other high entropy alloys is non-trivial due to the large number of elemental components. To investigate the preference for ordering in this alloy, materials were prepared by arc melting or melt-spinning followed by thermal annealing to vary the chemical homogeneity. Magnetization measurements show a dependence on cooling rate (i.e. preparation method) and thermal treatment, suggesting differences in the local chemical environments in this multicomponent alloy. The local chemical arrangements around Fe atoms were studied by ⁵⁷Fe Mossbauer spectroscopy between 77K and 300K. Preliminary results suggest that the different thermal treatments altered the local chemical environments in the alloy and that there are two chemical zones for bcc-phase Fe with different Curie temperatures. Correlations between the bulk magnetic properties and local chemical ordering will be discussed.