Surface modification by laser induced shock waves

Abstract

Laser shock surface treatment is a recently developed process designed to improve component fatigue life in a manner similar to conventional treatments such as shot peening. Irradiation with a short, intense laser pulse can be used to induce plastic strains and compressive residual stresses in metallic substrates. At laser energy densities above the threshold for melting and evaporation a hot plasma can form, expansion of which will induce a shock wave in the substrate, creating plastic strains. The effect of laser induced stress waves on residual stress, micro hardness, and surface quality of a standard steel have been investigated.