Fabrication and Analysis of Inconel 625 Parts using Wire and Arc Additive Manufacturing

Abstract

Superalloys based on Nickel are essential components in the aircraft industry and are extensively employed in the vital parts of aero engines. These parts are to be processed using traditional machining techniques and machining of these hard to machine materials is difficult and time consuming. Although numerous studies have been attempted to increase its machinability, their effectiveness was still limited. Additive manufacturing (AM) is an alternative method and is preferred in the modern manufacturing industries due to its high flexibility in fabricating complex parts, shorter manufacturing time, and reduced material waste. This method is applied for manufacturing medical, aerospace, marine, and nuclear components. Wire and Arc Additive Manufacturing (WAAM), a metal additive manufacturing technique that permits the fabrication of components at a high deposition rate with ease. Due to the high heat transfer during this process, it is necessary to provide pauses between the deposition of succeeding layers so that the workpiece integrity is preserved. In this research a method is developed for identifying heat accumulation behavior for the wire-arc additive manufacturing process using simulation. The simulation data is processed using idle times for the deposition of each layer to provide a steady inter-pass temperature. With the knowledge derived from simulation, the experiments are planned to study the influence of Inter-pass layer temperature on the microstructural mechanical characterization and corrosion behavior of Inconel 625. Three samples were additively manufactured for three different inter-pass layer temperatures (IPT) using the WAAM technique. The analysis shows that the grain morphology varies with different IPTs. Electron Backscatter Diffraction (EBSD) identified the grain size increase with increasing IPT. Grain boundary distribution angles also significantly varied with a change in IPTs. The variation in peak intensity identified the preferred crystal orientation through X-Ray Diffraction (XRD).