LAUSR

ABSTRACT The unusual mechanical and radiation properties found in concentrated solid–solution alloys (CSAs) make them promising candidate materials in nuclear applications. In this work, He behavior in a typical CSA, NiCFeCr, is assessed by first-principles calculations. Our results suggest that the energy difference of He in substitutional and interstitial sites is greatly reduced. The energy barriers of He through both interstitial and substitutional diffusion are much higher than those in pure Ni, indicating slower He dynamics in CSAs. The calculated activation energies show that the dissociation mechanism is more favorable in NiCoFeCr, which helps to suppress He growth as observed experimentally. GRAPHICAL ABSTRACT IMPACT STATEMENT For the first time, ab initio calculations reveal that the ease of He-vacancy cluster dissociation is the main mechanism responsible for the suppression of He bubble growth in concentrated NiCoFeCr alloys.