Laser surface processing of titanium in air: Influence of scan traces overlapping

Laser surface treatments of titanium in air have been performed through a pulsed Nd:yttrium-aluminum-garnet (lambda = 1.064 mum) laser. Several samples have been obtained modifying the laser scan velocity and partial overlapping of consecutive traces, in order to study the influence of these parameters on the surface morphology. Scanning electron microscopy and profilometry measurements have revealed different surface morphologies depending on the physical processes involved in the treatments. The surfaces are melted in all cases and present a different crack configuration depending on the melting regime. In addition, at low scan velocities, the presence of a laser generated plasma results in a periodic groove structure that evolve. to a flat and porous surface when the distance between traces is decreased. (C) 2003 Laser Institute of America.