摘要
In this work, three NiCoCr-based medium-entropy alloys (MEAs), i.e., NiCoCr, NiCoCrW 0.1 and NiCoCrTi 0.1 , were irradiated with helium (He) ions at 400 ℃ and 700 ℃ to study the radiation hardening and He-induced cavity growth behavior. The typical quaternary FeCoNiCr alloy was irradiated similarly and evaluated for comparison. Using transmission electron microscopy and nanoindentation measurements, He-induced microstructural evolution and mechanical changes were systematically investigated. Here we show that mitigated radiation hardening at 400 ℃ and cavity growth behavior at 700 ℃ were exhibited in the NiCoCr-based MEAs, in contrast to significant radiation hardening and He cavity growth of FeCoNiCr. Among the studied alloys, NiCoCrW 0.1 displayed the best radiation hardening resistance, while NiCoCrTi 0.1 presented the strongest tolerance in terms of He cavity growth. The underlying reasons were carefully analyzed based on the observed microstructures. Our results demonstrate the great potential of NiCoCr-based MEAs to function as critical nuclear structural components at relatively low and high temperatures.