LAUSR

ABSTRACT Surface integrity in electric discharge machining (EDM) has always been a major concern in the manufacturing industry. Although, EDM with a powder suspended dielectric has shown good potential in enhancing the material removal rate and improving surface finish, influence of the same on the overall surface integrity is not very clear. The current work utilized the graphite powder and evaluated its role in combination with concentration and machining parameters, on surface roughness (Ra), surface crack density (SCD), white layer thickness, microhardness depth profile, possible phase changes, and residual stress during powder-mixed EDM (PMEDM) of Inconel 625 (a nickel-based super alloy), that is now-a-days regularly used in aerospace, chemical and marine industries. The results showed that significant reduction in surface roughness, crack density, and white layer thickness is possible with the PMEDM process. It also promoted formation of carbides and other alloy compounds which is responsible for augmentation of hardness in surface and subsurface region. The added particles also caused a decline in tensile residual stress of the machined samples.