Effects of Laser Incident Angle Variation on Hardening of Metals in Laser Peening Experiments

Abstract

We investigated the effects of laser incident angle variation on the hardening of metal in laser peening experiments. We used full annealed SUS316L stainless steels as test samples. A 2nd harmonic of Nd:YAG laser light was used to produce laser-peened samples. We used Vickers microhardness tests to estimate the work hardening due to the plastic deformation caused by laser peening. The hardness of the laser-peened samples varied with the numerical aperture of the optics corresponding to the angle of incidence of the laser radiation. The hardness measurements revealed the desirable numerical aperture for laser peening experiments.