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. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4730327]