Enhanced radiation tolerance and plasticity in nanochannel Al_0.1CoCrFeNi high-entropy alloy

Irradiation-induced embrittlement is a critical and common issue for nuclear materials. Here, we find that the structural design of high-entropy alloy (HEA), nanochannel Al_0.1CoCrFeNi HEA, not only enhances the irradiation tolerance, but also significantly relieves the irradiation-induced embrittlement. We present a systematic investigation on the irradiation tolerance and the mechanical response of the nanochannel HEA irradiated by 40 keV He⁺ ions to the fluence of 5 × 10¹⁷ ions/cm² and by 2 MeV Ar⁺ ions to a fluence of 6 × 10¹⁶ ions/cm². It is uncovered that the nanochannel HEA exhibits better He management ability and radiation damage tolerance than its dense counterpart. Furthermore, nanoindentation tests show that the irradiated nanochannel HEA has a better mechanical response compared with its dense counterpart: (1) Strain rate sensitivity (SRS) exponent (m) of the nanochannel HEA has only a slight decrease compared to the large decrease for the dense HEA; and (2) the SRS exponent (m) of the nanochannel HEA is elevated while that of the dense HEA is consistently decrease after He⁺ ion irradiation. These results highlight that nanochannel structure with enormous free surface can mitigate the deleterious effects of irradiation as comparing with its dense counterpart, and represents a new promising strategy to design radiation tolerant materials for the advanced nuclear reactor systems.