Prediction of surface residual stress in laser-assisted micro-milling of Inconel 718

Residual stress distribution induced by laser-assisted micro-milling (LAMM) has a significant effect on the fatigue life, corrosion resistance, and dimensional stability of micro-scale components. Therefore, accurate prediction of residual stress is essential for process parameter optimization and control. During the LAMM of Inconel 718, laser heating increases the workpiece temperature, which promotes material softening but also induces thermal deformation and thermal strain. Moreover, due to the size effect inherent in micro-milling, residual stress prediction becomes challenging under complex thermo-mechanical coupling conditions. To address this issue, a finite element simulation-based method was proposed to predict the surface residual stress generated in LAMM. First, a simulation model of the LAMM process was established. Then, the temperature, stress, and strain fields obtained during the cutting stage were transferred to a subsequent implicit analysis to predict the residual stress. LAMM experiments on Inconel 718 were further conducted, and the surface residual stress was measured by X-ray diffraction to validate the proposed model. The results show that the developed model agrees well with the experimental measurements and can effectively predict the surface residual stress induced by LAMM. This study provides a basis for process parameter optimization in LAMM.