Preliminary assessment of the irradiation behaviour of the FeCrMnNi High-Entropy Alloy for nuclear applications

In the search for new nuclear materials with improved radiation tolerance and behavior, the high-entropy
alloys (HEAs) have arisen as new candidates for structural components in nuclear reactors due to their
suspected superior stability under irradiation. The metallurgical definition of HEAs is any alloy with
multiple elements, five or more all in equiatomic compositions. The basic principle is the high mixing
entropy of its solid solution lowers the Gibbs free energy giving a strong enhancement of the
microstructural stability at low and high temperatures.

The objective of this project is to assess the irradiation behaviour of the FeCrMnNi HEA system in order
to investigate whether the high entropy effect is responsible for a microstructure with better radiation
resistance compared to conventional alloys. In this work transmission electron microscopy (TEM) with
in-situ ion irradiation has been used at the MIAMI-1 facility at the University of Huddersfield, UK: a 100
kV ion accelerator coupled with a JEOL JEM-2000FX TEM. This methodology allows the evolution of
the HEA microstructure to be studied on the nanoscale during the ion irradiation.