Studies on Surface Topography and Metallurgical Aspects of EDMed Work Surface of Super Alloy Inconel 718

Abstract

A case experimental research towards investigating aspects of Electro-Discharge Machining (EDM) on Inconel 718 super alloy using Copper tool electrode has been delineated herein. Based on three controllable process variables viz. peak discharge current, pulse-on duration and gap voltage, experiments have been carried out to investigate their effects on influencing various process performance features like Material Removal Rate (MRR); Surface Crack Density (SCD) and White Layer Thickness (WLT) onto the top surface of the EDMed end product. Additionally, EDAX analysis has been carried out to investigate the extent of carbon enrichment onto the machined surface as affected during pyrolysis of the dielectric fluid whilst executing EDM operation. XRD tests have been carried out to compare metallurgy (various phases/precipitates present in bulk of the matrix material, extent of grain refinement, crystallite size, strain and dislocation density) of the EDMed work surface with respect to ‘as received’ Inconel 718. Results, thus obtained, have also been compared to that of micro-hardness test data.