Gas flow effect on the surface modification of aluminum and silver targets irradiated by a nanosecond laser

Abstract

This study investigates the surface modification of a material irradiated by a nanosecond Nd:YAG green laser while exposed to a gas flow. Scanning electron microscopy images and X-ray diffraction profiles illustrate the effect of laser irradiation in different environments, especially under backing gas pressures of 0.5, 1, and 1.5 bar applied through a supersonic nozzle. After irradiation, the microhardness obtained through the Vickers hardness increased by a factor of 3.40 and 4.90 for Al and Ag, respectively. This enhancement can be attributed to the surface and structural modification of the irradiated sample under different environments. Furthermore, the microhardness was found to be associated with the microstrain.