Abstract
A group of single-phase concentrated solid-solution alloys (SP-CSAs), including NiFe,
NiCoFe, NiCoFeCr, as well as a high entropy alloy NiCoFeCrMn, was irradiated with 3
MeV Ni2+ ions at 773 K to a fluence of 5×1016 ions/cm2 for the study of radiation response
with increasing compositional complexity. Advanced transmission electron microscopy
(TEM) with electron energy loss spectroscopy (EELS) was used to characterize the
dislocation loop distribution and radiation-induced segregation (RIS) on defect clusters in
the SP-CSAs. The results show that a higher fraction of faulted loops exists in the more
compositionally complex alloys, which indicate that increasing compositional complexity
can extend the incubation period and delay loop growth. The RIS behaviors of each
element in the SP-CSAs were observed as follows: Ni and Co tend to enrich, but Cr, Fe and
Mn prefer to deplete near the defect clusters. RIS level can be significantly suppressed by
increasing compositional complexity due to the sluggish atom diffusion. According to
molecular static (MS) simulations, “disk” like segregations may form near the faulted
dislocation loops in the SP-CSAs. Segregated elements tend to distribute around the whole
faulted loop as a disk rather than only around the edge of the loop.