Enhanced radiation resistance of W-based HEA under helium-ion irradiation conditions

Recently, high entropy alloy (HEA) has demonstrated superior radiation resistance to energetic particles. In this paper, we examine the radiation response of W-based HEA (WMoTaVNb) under the low-energy helium plasma exposure. As compared to pure W, WMoTaVNb demonstrated significant suppression in surface nanofuzz growth after the 65 eV helium plasma exposure to the same fluence (2 x 1024 He/m2). In addition, the 1 MeV helium ion implantation results present the sluggish helium bubble growth in W-based HEA, which is suspected to be the dominant cause to delay the nanofuzz growth. These results are further interpreted by comparing the transport of interstitial defects toward the surface regions in both pure W and W-based HEA via the molecular dynamic (MD) atomistic simulations. Our results show that due to chemical complexity, defect diffusion is highly localized in HEA, suggesting that the sluggish motion of interstitial defects may play another critical role in delaying surface nanofuzz growth if trap mutation and surface adatom formation mechanism dominates the fuzz growth.