Surface Quality Analysis of Titanium and Nickel-based Alloys Using Picosecond Laser

In order to evaluate the surface quality of ablated Ti-6Al-4V and Ni-Ti with a widely used 10-picosecond laser system with a wavelength of 1064 NM at a repetition rate of 5 kHz, three stages have been accomplished: i) study of the material removal mechanism on single cracters; ii) investigation of process parameters on surface finishing of linear tracks; iii) evaluation of the (sub-) surface of laser-ablated pockets. Through studying the influence of laser fluencies on single cracters, the evolution of component surface involved in the laser ablation has been obtained. This is further supported by investigating the threshold fluence, incubation effect and surface morphology of the ablated cracters. Ti-6Al-4V is found to have a higher incubation that indicates its weaker accumulation ability of heat of plastic deformation. Cavity-like structures are observed in the sectional surface, along the ablated surface. (C) 2014 The Authors. Published by Elsevier B.V.