Local Chemical Environments in Magnetic “High Entropy” Alloys

Science Center A247

Chemical and magnetic ordering in the body-centered cubic high entropy alloy FeCoCrNiAl2 were investigated. The materials were subjected to thermal treatments by various methods including melt spinning and arc melting followed by quenching from various temperatures. Previously measured magnetic properties have shown a dependence on thermal treatment, raising the belief that such treatments have altered the local chemical environments in this multicomponent alloy. The local chemical arrangements around Fe atoms were studied by 57Fe Mossbauer spectroscopy at both room temperature and at 77K where the samples are strongly ferromagnetic. Preliminary results show that the different thermal treatments altered the local chemical environments in the alloy. These results will be correlated to changes in the bulk magnetic properties with thermal treatment. Changes in the configurational entropy of these "high entropy" alloys will also be estimated.