Correlative SEM-EDS-XRD Characterization of Surface Modification in LPBF Inconel 718 after Wire Electrical Discharge Machining

Abstract Laser powder bed fusion (LPBF) enables near-net-shape production of Inconel 718 components, but electrically conductive post-processing is often required to obtain final dimensions and accessible cut surfaces. This study presents a before-after characterization of LPBF Inconel 718 subjected to one fixed wire electrical discharge machining (WEDM) condition. The comparison is intentionally limited to the available paired scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) dataset and does not claim process-parameter optimization. The pre-WEDM LPBF surface displayed heterogeneous relief, locally adhered material, and track-like surface features, whereas the WEDM-cut surface exhibited crater-like depressions, globular resolidified particles, adhered debris, and localized crack-like discontinuities. EDS showed marked near-surface compositional changes: oxygen increased from 0.66 to 9.13 wt.%, copper from 0.68 to 5.65 wt.%, and zinc changed from below detection to 3.89 wt.%, consistent with oxidation and transfer from the brass wire electrode. The elevated carbon signal after WEDM is treated cautiously because deionized water was used as the dielectric and the available dataset does not exclude preparation or surface-contamination artefacts. XRD retained the dominant facecentred cubic gamma-Ni reflections after machining; apparent peak-position changes were observed, but they are not interpreted quantitatively as residual stress because calibration and peak-fitting uncertainty were not available. The combined results indicate that the selected WEDM operation produced pronounced morphological and chemical modification of the near-surface region while preserving the dominant bulk matrix phase. The study provides a transparent baseline for subsequent quantitative work on roughness, recast-layer thickness, residual stress, fatigue, and corrosion.