Study of selective laser melting (SLM) Inconel 718 part surface improvement by electrochemical polishing

Abstract

Electrochemical polishing (ECP) was used to improve surface quality of Inconel 718 components fabricated by selective laser melting (SLM). In this study, SLM Inconel 718 tube part surface was processed by electrochemical polishing by pre-optimized parameters. The surface morphology and roughness evolution with different electrochemical polishing duration were characterized by scanning electron microscopy (SEM) and 3D surface profilometer. The surface roughness can reach as low as 3.66μm (Ra), compared with the initial surface roughness of 6.05μm. Microstructure and XRD study indicated that the δ and carbide phase were revealed under ECP with long duration instead of γ phases on the original sample surface. In order to identify the mechanical properties of the surface, nano-indentation tests were carried out on both the original sample surface and the sample surface after ECP. The results showed that the samples after ECP possess a relatively lower surface hardness and surface elastic modulus.