Absence of Long-Range Chemical Ordering in Equimolar FeCoCrNi

Equimolar FeCoCrNi alloys have been the topic of recent research as high-entropy alloys, where the name is derived from the high configurational entropy of mixing for a random solid solution. Despite their name, no systematic study of ordering in this alloy system has been performed to date. Here, we present results from anomalous x-ray scattering and neutron scattering on quenched and annealed samples. An alloy of FeNi3 was prepared in the same manner to act as a control. Evidence of long-range chemical ordering is clearly observed in the annealed FeNi3 sample from both experimental techniques. The FeCoCrNi sample given the same heat treatment lacks long-range chemical order.
Published in Applied Physics Letters, v100 article ID 251907, 20 Jun 2012. Prepared in cooperation with UTC, Inc., Dayton, OH, UES, Inc., Dayton, OH, California Institute of Technology, W. M. Keck Laboratory, Pasadena, Wright State University, Dayton, OH, Oak Ridge National Laboratory, Oak Ridge, TN and Argonne National Laboratory, Argonne, IL.