Measurement of laser peening residual stresses

AbstractLaser peening is an emerging surface treatment for metals that imparts compressive residual stress near the surface by introducing cold work. The present paper describes two residual stress measurement techniques that are well suited for the measurement of residual stresses induced by laser peening. Since residual stress is a key outcome of the laser peening process, its measurement is an important process diagnostic. The two residual stress measurement techniques described are the slitting method and the contour method. In the present research, the slitting method is used to establish relationships between various laser peening parameters (irradiance, pulse duration, number of layers, etc.) and the residual stress profile (residual stress versus depth) in flat plate coupons that have been uniformly peened on one surface. This helps to identify an effective set of laser peening parameters for the given material. Next, laser peening is applied to a specimen(s) with representative geometry and the c...