Effect of laser welding on the microstructure and properties of ultrathin Inconel 718 sheets

Inconel 718 is a high-strength, high-temperature alloy with a nickel matrix containing elements such as niobium (Nb) and molybdenum (Mo). It exhibits excellent corrosion resistance and high-temperature mechanical properties. It is widely used in the manufacture of critical sealing components. However, there is currently limited research on the welding of ultra-thin Inconel 718 sheets with a thickness of 0.25 mm. To address issues such as deformation and poor fusion during welding, this study proposes a combined approach of finite element simulation and experimental analysis to investigate the effects of pulsed laser welding parameters on the temperature field, weld morphology, and mechanical properties. The optimal process parameters obtained through orthogonal experiments were a laser power of 300 W, a welding speed of 60 mm/s, and a duty cycle of 55%. The results show that, with these parameters, the tensile strength of the weld was 856 MPa, approaching 80% of that of the base material, and the weld morphology was uniform and defect-free. The experimental and finite element simulation results were in good agreement. The microstructure at the weld was compact and uniform, with a reasonable distribution of Laves and δ phases, and no obvious defects were observed. This study provides valuable reference data for designing the actual laser welding process for Inconel 718 thin sheets.