Femtosecond and Nanosecond Laser Peening of Stainless Steel

Ablation of material can be obtained by high intensity laser beams and resulting in crater formation in samples. Crater morphology is due to concurring processes: subsurface vaporization, heterogeneous or/and homogeneous boiling, subsurface heating, spherical shock wave propagation, and the volume of craters is expected to be inversely proportional to the bulk modulus of target material. FIB-SEM dual beam system can be used to investigate the role of mechanical and thermal material properties in the laser produced crater morphology. In particular, FIB-SEM images of craters in conductive samples show a higher deposition around craters than in insulators, due to the different thermal conductivity of materials. Due to subsurface modifications on samples, both circular and noncircular craters may be formed. Therefore the analysis of the profile of these structures can be used to back up at dissimilar laser ablation processes