Tailoring the radiation tolerance of eutectic high-entropy alloy via phase-composition control

Eutectic high-entropy alloys (EHEAs) take advantage of heterogeneous crystal structures, numerous interfaces, and multicomponent composition designs, implying a potential radiation tolerance in the nuclear environment. In this work, we employed the He ion irradiation to study the irradiation behavior of two types EHEAs (Fe42Ni31Al17Cr10, abbreviated as Fe42, and Fe47Ni26Al17Cr10, abbreviated as Fe47) with different phase designs. The results showed that the FCC + B2 constituted Fe42 EHEA and BCC + B2 constituted Fe47 EHEA retained their general phase-composition features up to similar to 1.2 dpa at 1073 K, while the long-range order of B2 phase was slightly disrupted in both alloys and more severe in the Fe42 EHEA. The quantification on He bubbles formation in different phases further indicated that the ordered B2 phase in Fe47 EHEA has a superior radiation resistance with smaller bubble size and less population. The differences in phase compositions and structures were believed to influence the vacancy-mediated helium diffusion during irradiation, which can account for the He bubble behaviors in the two kinds of alloys. The analysis on the width of bubble denuded zone along the phase boundary further suggested a higher energy barrier for the vacancy migration in the B2 phase, which consistently supported our inference on the underlying mechanism of bubble formation resistance of Fe47 EHEA. We believe that this work will provide a new strategy for designing EHEAs with excellent resistance to irradiation at elevated temperatures.

Automated summary

In this study, the irradiation behavior of two types of EHEAs (Fe42 and Fe47) with different phase designs was investigated using He ion irradiation. The results showed that the phase composition of the alloys remained relatively stable up to a certain level of irradiation, but the long-range order of the B2 phase in Fe42 alloy was disrupted to a greater extent. It was also found that the Fe47 alloy with an ordered B2 phase exhibited better radiation resistance, with smaller and fewer helium bubbles formed. This work provides a new strategy for designing EHEAs with excellent resistance to irradiation at elevated temperatures.