Effects of laser-peening parameters on plastic deformation of SUS316L

Effects of laser-peening parameters on plastic deformation have been investigated through hardness measurements. The laser-peening parameter consisting of laser parameters, pressure of laser-produced plasma, propagation of laser-induced shock wave and initial state of target material should be optimized for efficient laser peening. The laser parameters are one of the important factor, thus laser intensity and coverage which corresponds to the number of laser shots irradiated per unit of area have been changed to estimate the laser peening effect in this study. Second harmonic of Nd:YAG laser having the pulse duration of 4 ns has been used. Commercial SUS316L stainless steel has been adopted as a sample. The samples were investigated under nanosecond laser-shock loading in plasma confined by water. Vickers microhardness is used to probe work hardening due to plastic deformation induced by laser peening. Through hardness measurements, it is found that desirable coverage for producing the plastic deformation has been existed, which depends on the laser irradiation intensity.