Internal stresses and hardness of alloys based on the V-Nb-Ta-Ti system irradiated with helium ions

The changes in internal stresses and mechanical properties of V‑Nb-Ta-Ti alloys manufactured by arc melting after irradiation with He²⁺ ions (40 keV) to a fluence of 2 ⋅ 10¹⁷ cm⁻² are studied. The irradiation of V, VNb, and VNbTa alloys is shown to decrease the compressive macrostresses in the pre-peak region and increase them for V and VNbTa in the peak region of helium implantation. The irradiation of a VNbTaTi high-entropy alloy increases the compressive macrostresses by 44% and 50% in the two regions, respectively. The dislocation density is observed to increase significantly. The elastic modulus of VNbTa and VNbTaTi was stable, but decreased for V and VNb. The degree of hardening is the highest for V and VNb (99% and 52%, respectively) and the lowest—for VNbTa and VNbTaTi (29% and 45%, respectively). The influence of macrostresses and dislocation density on the hardness of V‑Nb-Ta-Ti alloys irradiated with He is established. VNbTaTi shows a higher radiation resistance compared to that of V, VNb, and VNbTa.