Thermomechanical Process Simulation and Experimental Verification for Laser Additive Manufacturing of Inconel^®718.

Laser cladding is widely used for fabricating and repairing metal components. However, the process involves repeated melting and solidification, which can lead to residual stresses and distortions. These issues affect the final product's geometry and performance. While prior research has shown that residual stresses arise from thermal cycling, the precise mechanisms remain unclear. Computational models have been developed to predict these effects, but their accuracy has been limited. Experimental validation is often lacking, making it difficult to refine simulation techniques. The challenge lies in capturing the dynamic nature of powder deposition and its impact on stress distribution. Existing models struggle to balance computational efficiency with physical accuracy. This gap motivates the need for a more robust simulation framework. A better understanding of residual stress and distortion could improve laser additive manufacturing outcomes.

This study aimed to develop and validate a thermomechanical simulation approach for laser additive manufacturing of Inconel®718. The primary goal was to predict residual stresses and geometric distortions in multilayer laser cladding. The researchers focused on improving computational accuracy while maintaining efficiency. They sought to bridge the gap between simulation and experimental results. By using a hybrid finite element method (FEM), they aimed to model the transient temperature field and stress distribution. The study also aimed to verify simulation results with physical measurements. The motivation was to provide a reliable predictive tool for additive manufacturing. Accurate predictions could help optimize process parameters and reduce defects.

The researchers employed a hybrid finite element method (FEM) to simulate the laser cladding process. They modeled the transient material deposition and powder consolidation behavior. The simulation tracked temperature changes and stress evolution during each layer's formation. The model incorporated material properties of Inconel®718 and laser parameters. A transient heat transfer analysis was conducted to capture thermal gradients. Residual stress was calculated using a coupled thermomechanical approach. The simulation results were compared with experimental data. X-ray diffraction (XRD) and coordinate measuring machine (CMM) were used for validation.

The simulation predicted a maximum tensile residual stress of 373 ± 5 MPa in the middle of the substrate layer. This value closely matched the experimental XRD measurements. The geometric distortion was measured at 0.68 ± 0.01 mm using a coordinate measuring machine. The simulation results showed precise agreement with the experimental data. The hybrid FEM approach accurately captured the temperature field dynamics. The model effectively predicted stress distribution across multiple layers. The study confirmed that the simulation could replicate the physical process. The results demonstrated the model's reliability in predicting residual stresses and distortions.

The hybrid FEM approach demonstrated robust performance in predicting residual stresses and distortions in laser cladding. The simulation results were validated with experimental measurements, confirming the model's accuracy. The study showed that the model can replicate the physical behavior of multilayer laser cladding. The close agreement between simulation and experiment supports the model's reliability. The findings suggest that this approach can be used to optimize process parameters. The model's efficiency makes it suitable for industrial applications. The study's results align with the authors' claims about simulation accuracy. The hybrid method provides a reliable tool for additive manufacturing process design.