Effect of pre-damage induced by argon ions on the following 60 keV helium ions irradiation behavior of tungsten-tantalum alloy

W-5 %Ta specimens were irradiated by 800 keV Ar⁸⁺ ions at a fluence of 5.27 × 10¹⁷ ions/m², then under exposure to 60 keV He²⁺ ions to a fluence of 1.04 × 10²² ions/m². In this paper, an effect of Ar⁸⁺ ions pre-damaged on the following He²⁺ irradiation behavior of W-5 %Ta is reported. These results suggest that the size of large helium blisters on the surface of W-5 %Ta could be effectively reduced by the Ar⁸⁺ ions pre-damage. However, the helium retention was found to be systematically higher in the pre-damaged W-5 %Ta. Ar⁸⁺ ions pre-damage can greatly enhance the intensity of helium release peaks at low temperature (<650 K). In addition, the hardness of undamaged and pre-damaged W-5 %Ta is approximately 7.3 and 9.8 GPa, respectively, indicating that the damage induced by Ar⁸⁺ ions irradiation has a significant effect on the mechanical properties of W-5 %Ta.