Weakening the self-trapping of helium by electron density regulation in WTaVCr high-entropy alloys

Abstract

High-entropy alloys (HEAs) have been demonstrated to show a particular suppressing effect on helium (He) bubbles, but the mechanism behind it remains unclear. Herein, we systematically investigate the dissolution and nucleation of He in WTaVCr HEAs by first-principles method combined with thermodynamic model. It is found that the solution energies of He in WTaVCr are much lower than that in pure W, because of the regulation of electron density by various components in WTaVCr. More importantly, this effect leads to a significant decrease of He-He binding energy in WTaVCr, which is at least 50% lower than that in pure W. This difference increases with increasing cluster size, indicating that the “self-trapping” of He will be significantly weakened in WTaVCr, thereby suppressing He blistering. Our finding provides new insights into the suppression of He-induced radiation damage in nuclear materials.