Structural and Phase Changes in Concentrated V–Nb–Ta–Ti Solid Solutions Irradiated by Helium Ions

Abstract: The effect of irradiation by low-energy helium ions with a fluence of 2 × 10¹⁷ cm^–2 and an energy of 40 keV on the structure and phase state of V–Nb–Ta–Ti solid solutions is studied to obtain data on the radiation resistance of multicomponent solid solutions promising for use as structural materials of new generation reactors. It is established by scanning electron microscopy and X-ray diffraction analysis that the synthesized binary, ternary, and quaternary V–Nb–Ta–Ti alloys are equiatomic single-phase solid solutions with a uniform element distribution over the surface and compressive microstresses and macrostresses. It is shown that irradiation of the V–Nb–Ta–Ti alloys by helium ions leads to neither the decay of a solid solution nor violation of the uniform equiatomic distribution of elements over the surface. Irradiation by helium ions does not significantly change the level of microstresses and macrostresses in the VNb and VNbTa systems, while in the VNbTaTi alloy the compressive-stress level increases, which can be related to the segregation of elements to grain boundaries and the accumulation of helium-vacancy clusters.