Characterization of ion induced damage as a function of depth in proton irradiated pure Ti and Ti-6Al-4V

The inhomogeneous damage caused by ion irradiation (proton) as a function of depth has been characterized on pure Ti and Ti-6Al-4V at different doses. X-ray line profile analysis was used to evaluate the microstructural parameters such as domain size and microstrain within the domain. Although a systematic decrease in domain size as a function of depth is observed in both the materials, but the changes are less prominent in Ti-6Al-4V than in pure Ti. The increase in the value of S-parameters measured from Doppler Broadening Spectroscopy of Positron annihilation technique reveals higher concentration of open volume defects near Bragg peak (maximum damage region). Micro-hardness is also measured as a function of depth for both irradiated and unirradiated samples. The results obtained from micro-hardness measurements are found to corroborate with the findings from PAS and XRDLPA. Radiation induced segregation (RIS) which was observed in the Ti-6Al-4V at the highest dose 5E17p/cm(2) is found to be limited near to the surface. Detailed X-ray analysis using Convolutional Multiple Whole Profile fitting of the XRD data from the surface of the irradiated Ti-6Al-4V samples could reveal the nature of the dislocations (i.e. or type). (C) 2019 Elsevier B.V. All rights reserved.