Effect of irradiation with helium ions and subsequent annealings on the crystal structure of alpha titanium

Titanium and its low-alloy mixtures are being considered as possible structural materials for future fusion reactors. Toward this end the authors undertook an x-ray study of the structure of alpha-titanium, obtained by the iodide method, and allow VT1-0, both irradiated with helium 4 ions in an electrostatic accelerator, and of the structural changes during subsequent thermal annealings. Three samples of alpha titanium and one sample of alloy VT1-0 were irradiated to different helium concentrations. X-ray analysis was carried out by means of precise measurement of the location, amount of broadening, and intensity of the diffraction maxima. X-ray line broadening increased with a rise in helium concentration. Annealing of the irradiated samples of iodide titanium caused a change in the lattice periods and broadened the diffraction lines. Structure evolution of hcp alpha-titanium irradiated with helium 4 ions and then annealed differed from that seen in materials with fcc lattices