Characterization of high energy ion implantation into Ti-6Al-4V

Ion implantation is a surface modification process that can improve the wear, fatigue, and corrosion resistance for several metals and alloys. Much of the research to date has focused on ion energies less than 1 MeV. With this in mind, Ti-6Al-4V was implanted with Al2+, Au3+, and N+ ions at energies of 1.5 and 5 MeV and various doses to determine the effects on strengthening of a high energy beam. A post heat treatment on the specimens implanted with Al2+ samples was conducted to precipitate TixAl type intermetallics near the surface. Novel techniques, such as nanoindentation, are available now to determine structure-mechanical property relationships in near-surface regions of the implanted samples. Thus, nanoindentation was performed on pre-implanted, as-implanted, and post heat treated samples to detect differences in elastic modulus and hardness at the sub-micron scale. In addition, sliding wear tests were performed to qualitatively determine the changes in wear performance. The effect of this processing was significant for samples implanted with Al2+ ions at 1.5 MeV with a dose higher than 1 × 1016 ions/cm2 where precipitation hardening likely occurs and with N+ ions.