INFLUENCE OF GRAIN SIZE ON THE STRUCTURE AND PHASE COMPOSITION OF VT1-0 ALLOY IMPLANTED WITH ALUMINUM IONS

10.25712/ASTU.1811-1416.2023.02.002

Abstract

The structural-phase state of the surface layers of technically pure titanium (alloy grade BT1-0) implanted with aluminum ions in three states was investigated by transmission electron diffraction microscopy and energy dispersive X-ray spectroscopy on foils cut perpendicular to the machined surface of the sample: submicrocrystalline, ultrafine-grained and fine-grained, obtained after a combined method of multiple uniaxial pressing (abc-pressing) followed by multiple passes rolling in brook rolls at room temperature and subsequent annealing at 573, 673 and 773 K, 1 h, respectively. Ion implantation was performed for 8 hours and 20 minutes, an irradiation dose of 10×10¹⁷ ions/cm² and a temperature of 623 K. It was found that implantation led to the formation of a gradient structure consisting of 5 layers. For each layer its thickness, phase composition, shape and arrangement of the second phase particles were determined, the size of the a-Ti grains, the size, density of distribution and volume fractions of the separated particles were measured. It is established that implantation led to the formation of intermetallic phases Ti₃Al and TiAl₃. The particles Ti₃Al have a lamellar shape and are located inside part of the a-Ti grains, the particles TiAl₃ have a rounded shape and are located randomly.