Surface integrity induced in machining additively fabricated nickel alloy Inconel 625

Abstract

Abstract Parts fabricated with metal additive manufacturing processes such as laser powder bed fusion (LPBF) or laser metal deposition have much different microstructure than cast or wrought counter parts. Machining processes employed on these parts to finish them to their final net shape and surface quality add further complexity to the subject. The machined surface morphology has an important effect on the service performance of components, including fatigue life, wear resistance and corrosion resistance, and is closely related to machining conditions. It is essential to investigate the effect of machining on the surface morphology of additively fabricated workpieces. This paper investigates surface topography and surface integrity of machined nickel alloy Inconel 625 test workpieces that were built using LPBF with two different scan strategy orientations. The results indicate that the surface topography and integrity is affected by relative orientation of cutting direction to the build direction and scan strategy orientation. Finished surfaces indicative of surface defects such as feed marks, material side flow, adhered materials, and smeared materials were also investigated. It is evident that surface integrity can be significantly improved by an optimized milling process.