Characterization of the Anisotropic Behaviour of Inconel 718 Parts Manufactured by Wire Arc Additive Manufacturing

Abstract

The usage of additive manufacturingAdditive manufacturing as a process for component production is becoming increasingly important, as it offers enormous potential for material savings and therefore cost reduction. In particular, Wire Arc Additive ManufacturingWire-arc additive manufacturing (WAAM) processes are arousing a great deal of interest in several industries by its high deposition rates at low equipment acquisition costs and the low buy-to-fly ratio. This process is being specifically investigated for aerospace and space applications, as it allows the production of large structural complex near-net-shape components in small batches. However, a major drawback of this technology is the high anisotropic behaviour of the manufactured structures in the as-welded state. Since the Ni–Fe alloy Inconel 718Inconel 718 is an anisotropic material, in which introduced textures strongly influence the mechanical propertiesMechanical properties, the impact of the WAAM processing route on the mechanical propertiesMechanical properties as well as the underlying microstructureMicrostructures is specifically focused on in this study. Using a plasma arc as heat source and Inconel 718Inconel 718 wire as feedstock material, test walls are produced in order to characterize the created material. In addition to the identification of factors influencing the process, temperature cycles are measured at different positions during the build-up. The resulting microstructureMicrostructures is subsequently evaluated macroscopically as well as microscopically and examined regarding pores and precipitates. SEM/EDS analysis is carried out to investigate the underlying microstructureMicrostructures of the additively manufactured parts. Furthermore, mechanical propertiesMechanical properties are evaluated in the build-up direction as well as transversal to this direction in order to characterize the anisotropyAnisotropy of the material.