Microstructure of Ti–5Al–4V–2Zr alloy in the initial condition and after irradiation with titanium ions

Chemical analysis of phases and inclusions in a specimen of Ti–5Al–4V–2Zr titanium alloy in the initial state and after irradiation with titanium ions up to the radiation damage dose of ~1 dpa at 260°C was carried out and the microstructure was studied. Microstructural analysis was performed by the methods of transmission electron microscopy, energy dispersion X-ray spectroscopy, and atom probe tomography. Results of the chemical analysis of the matrix α phase and inclusions of β phase grains are given. It is shown that the α phase is enriched in aluminum up to 10 at % and the β phase is enriched in vanadium up to 20 at % in the initial state in the Ti–5Al–4V–2Zr alloy. Heavy ion irradiation induces the formation of dislocation loops of 3 to 12 nm with the number density of ~1022 m–3. A high number density (up to ~1024 m–3) of nanoscale precipitations with the average size of ~2 nm is formed during alloy irradiation in the α phase.