A finite element analysis of thermal relaxation of residual stress in laser shock processing Ni-based alloy GH4169

• Residual stress changed in the LSP-worked zone with different laser energy.
• The thermal stress relaxation influenced by heating temperature and exposure time.
• A large portion of total relaxation occurred in the initial period of exposure.

The residual stress induced by laser shock processing and the thermal relaxation behaviors of residual stress in Ni-based alloy GH4169 were investigated by means of three-dimensional nonlinear finite element analysis. To study the effect of different given exposure time and different temperatures on residual stress in laser shock processing Ni-based alloy GH4169, Johnson–Cook material model was used in order to account for the nonlinear constitutive behavior. The influence of heating temperature and exposure time on the stress thermal relaxation was studied. It was concluded that stress relaxation mainly occured during the initial period of exposure, and the degree of relaxation increased as the temperature risen. The results would provide a theoretical basis for controlling the laser shock processing and guiding subsequent experiments.