Microstructure and corrosion behavior of laser induced periodic patterned titanium based alloy

In this study, the effect of laser induced periodic patterning of - titanium alloy (Ti-6Al-4V) developed by excimer laser (ArF, with a laser fluence of 2.4 J/cm2, a laser pulse repetition rate of 200 Hz and 50 laser pulses) and Fiber laser (using a power of 5W, frequency of 80 kHz, scan speed of 800 mm/s and 2 times scanning) on its microstructure and corrosion behaviour have been investigated. The microstructure of the patterned surface shows a significant refinement of grains with the presence of alpha and beta. A very low mass fraction of TiO2 was noticed when patterning was performed using ArF laser. A significant improvement in total surface energy (from 37 mN/m for Ti-6Al-4V to 41 mN/m for ArF laser patterned surface and 40 mN/m for Fiber laser patterned surface) and polar energy (from 11 mN/m for Ti-6Al-4V to 26 mN/m for ArF laser patterned surface and 24 mN/m for Fiber laser patterned surface) have been observed. Corrosion rate was reduced due to laser patterning (from 6.12 mm/year for as-received Ti-6Al-4V to 2.17 × 10-2 mm/year for ArF laser patterned and 1.68× 10-2 mm/year for Fiber laser patterned Ti-6Al-4V surfaces). Laser surface patterning improved apatite deposition from 15 % area coverage for Ti-6Al-4V to 34% and 33% area coverage for ArF and Fiber laser patterned surfaces, respectively.