Search for Short-Range Ordering in Medium-Entropy Alloys

This report introduced the results of recent neutron scattering and X-ray absorption fine structure（EXAFS）experiments on a family of medium-entropy alloys（TrCoNi, Tr＝Cr, Mn, and Fe）. Neutron experiments revealed that the time-temperature-dependent short- and long-range structural transformation occurs in a medium-entropy alloy MnCoNi. Although a sign of short-range ordering was not clear in the EXAFS results, the mean-square relative displacement（MSRD）may catch the difference in local structures between medium-entropy alloys. The relatively large static MSRD of the MnCoNi sample can be interpreted as a sign of short-range tetragonal structural transformation, whereas the small value of the CrCoNi sample cannot be interpreted straightforwardly. A possible interpretation of the difference in MSRD was provided.