Finite Element Isight-Based and Experimental Parametric Optimization of the Thermo-Mechanical Behavior for Inconel 718 during the Wire Arc additive Manufacturing Process

Abstract

This study presents a multi-method optimization framework integrating analytical modeling, Isight-coupled ABAQUS finite element (FE) simulation, and experimental validation to optimize the thermo-mechanical behaviour of Inconel 718 fabricated by the wire arc additive manufacturing (WAAM) process. The effects of key process parameters, welding speed, and wire diameter on thermal distribution, residual stress, and mechanical performance, including tensile strength, microhardness, and Charpy impact energy, were systematically investigated. New analytical constitutive models were developed and compared with experimental data and FE simulation results from the Isight–ABAQUS workflow to improve prediction accuracy and support parametric optimization. The results indicate that welding speed is the most influential factor governing temperature gradients, residual stress evolution, and overall mechanical performance. The FE simulations showed strong agreement with experimental findings, with a maximum deviation of 4% in tensile strength, confirming their reliability for predictive modeling and optimization. X-ray diffraction analysis revealed compressive residual stresses in the WAAM-processed samples, as evidenced by peak shifts in the diffraction patterns compared to the feedstock wire. FE analysis further indicated high residual stresses at the substrate interface and notable thermal distortions in thin-wall structures. Three wire diameters (0.5, 1.0, and 1.5 mm) and three welding speeds (500, 700, and 900 mm/min) were examined at a constant deposition rate of 2 kg/hr. The optimal combination of 0.5 mm wire diameter and 900 mm/min welding speed yielded the highest tensile strength and hardness. Hardness mapping across different regions showed that the top surface had the highest hardness, due to localized rapid cooling and steep thermal gradients. Overall, the novelty of this work lies in the development of a new analytical constitutive model, its integration with Isight–Abaqus simulations, and experimental validation into a unified predictive framework for accurate optimization of thermomechanical responses in WAAM-fabricated Inconel 718 components.