Surface texturing of the carbon steel AISI 1045 using femtosecond laser in single pulse and scanning regime

Surface texturing of the metals, including steels, gained a new dimension with the appearance of femtosecond lasers. These laser systems enable highly precise modifications, which are very important for numerous applications of metals. The effects of a Ti:sapphire femtosecond laser with the pulse duration of 160 fs, operating at 775 nm wavelength and in two operational regimes - single pulse (SP) and scanning regime, on a high quality AISI 1045 carbon steel were studied. The estimated surface damage threshold was 0.22 J/cm² (SP). Surface modification was studied for the laser fluences of 0.66, 1.48 and 2.37 J/cm². The fluence of 0.66 J/cm², in both working regimes, induced texturing of the material, i.e. formation of periodic surface structures (PSS). Their periodicity was in accordance with the used laser wavelength. Finally, changes in the surface oxygen content caused by ultrashort laser pulses were recorded.