Process Optimization and Microstructural Characterization of Inconel 718 Fabricated via Wire Arc Additive Manufacturing

Abstract

Inconel 718, a widely used nickel-based superalloy, finds extensive applications in aerospace components, nuclear reactors, turbine blades, and rocket engines. It is also among the most commonly used materials in metal additive manufacturing. Wire arc additive manufacturing (WAAM), particularly using gas metal arc welding, has emerged as a promising technique for fabricating larger metal parts quickly and cost-effectively. This study investigates the mechanical properties, microstructure, and phases of Inconel 718 fabricated through WAAM. A Box–Behnken design (BBD) under response surface methodology (RSM) was employed to optimize parameters for maximum bead width (BW) and bead height (BH). ANOVA was used to analyze the influence of current, voltage, and travel speed on deposition quality. Optimal results were achieved at process parameters of 370 A, 13.5 V, and 50 mm/min, yielding a maximum BW of 9.78 ± 2.1 mm and BH of 7.28 ± 1.2 mm. Microstructural analysis revealed columnar dendrites and irregular interdendritic zones due to rapid solidification. The average microhardness was 272 ± 20.4 HV, with a tensile strength of 788 ± 1 MPa, yield strength of 345 ± 20 MPa, and elongation of 74.3 ± 0.5 %, indicating excellent strength and ductility for high-performance applications. Therefore, this work demonstrates the potential of an in-house-built WAAM setup for fabricating Inconel 718 with enhanced mechanical and microstructural performance through single-layer parameter optimization. © ASM International 2026.