Title:
Investigation of the effect of process parameters on the formation of recast layer in wire-EDM of Inconel 718

dc.contributor.advisor Melkote, Shreyes N.
dc.contributor.author Newton, Thomas Russell en_US
dc.contributor.committeeMember Danyluk, Steven
dc.contributor.committeeMember Liang, Steven Y.
dc.contributor.department Mechanical Engineering en_US
dc.date.accessioned 2008-06-10T20:38:26Z
dc.date.available 2008-06-10T20:38:26Z
dc.date.issued 2008-02-15 en_US
dc.description.abstract Inconel 718 is a high nickel content superalloy possessing high strength at elevated temperatures and resistance to oxidation and corrosion. The non-traditional manufacturing process of wire-electrical discharge machining (EDM) possesses many advantages over traditional machining during the manufacture of Inconel 718 parts. However, certain detrimental effects are also present. The top layer of the machined surface is melted and resolidified to form what is known as the recast layer. This layer demonstrates microstructural differences from the bulk workpiece, resulting in altered material properties. An experimental investigation was conducted to determine the main machining parameters which contribute to recast layer formation in wire-EDM of Inconel 718. It was found that average recast layer thickness increased with energy per spark, peak discharge current, current pulse duration, and open-voltage time and decreased with sparking frequency and table feed rate. Over the range of parameters tested, the recast layer was observed to be between 5 and 10 μm in average thickness, although highly variable in nature. Surface roughness of the cut parts showed an increase with energy per spark. Electron Probe Microanalysis (EPMA) revealed the recast layer to be alloyed with elements from the wire electrode. X-ray diffraction testing showed the residual tensile stresses evident near the cut surface to decrease with energy per spark. Additionally, nano-indentation hardness testing indicated that the recast layer is reduced in hardness and elastic modulus compared to the bulk material. Vibratory tumbling was found to be a moderately effective post-processing tool for recast layer removal when using pre-formed ceramic abrasive media or fine grained aluminum oxide. en_US
dc.description.degree M.S. en_US
dc.identifier.uri http://hdl.handle.net/1853/22580
dc.publisher Georgia Institute of Technology en_US
dc.subject Nano-indentation hardness testing en_US
dc.subject X-ray diffraction en_US
dc.subject Electron probe microanalyzer en_US
dc.subject Scanning electron microscope en_US
dc.subject XRD en_US
dc.subject EPMA en_US
dc.subject SEM en_US
dc.subject.lcsh Heat resistant alloys
dc.subject.lcsh Inconel
dc.subject.lcsh Machining
dc.subject.lcsh Electric metal-cutting
dc.title Investigation of the effect of process parameters on the formation of recast layer in wire-EDM of Inconel 718 en_US
dc.type Text
dc.type.genre Thesis
dspace.entity.type Publication
local.contributor.advisor Melkote, Shreyes N.
local.contributor.corporatename George W. Woodruff School of Mechanical Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication e78c9d4f-2d4a-4337-9739-f9179a9fd7fb
relation.isOrgUnitOfPublication c01ff908-c25f-439b-bf10-a074ed886bb7
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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