Ti-6Al-4V Surfaces in SiC Powder Mixed Electrical Discharge Machining

Abstract

The role of suspended particles on Ti-6Al-4V surface in Powder Mixed Electrical Discharge Machining (PMEDM) is studied using SiC powder mixing in water dielectric liquid. Surface modifications due to the additives in dielectric liquid are investigated by means of optical, scanning electron microscopy and energy dispersive spectroscopy. The attachment of added powders and surface topographies interrelated with powder suspension concentration, particle size and electrical parameters such as pulse on duration and current. The influence on discharge transitivity with respect to SiC additives is noticed with pock like features on the surface. The geometry and size of these features indicated a robust dependency with respect to operational parameters and indicated the role of secondary discharges during PMEDM. SiC particles severely transferred from di-electric liquid to machined surface at critical operational parameters and implied that the process could be also used as a surface alloying technique.

Particle migration and surface modification on Ti6Al4V in SiC powder mixed electrical discharge machining

“…SiC powder addition in water dielectric liquid revealed various types of topographical features on Ti-6Al-4V surfaces suggesting machining is accompanied by subdivided electrical discharges in different forms [18,19]. Moreover, the material migration phenomenon from the dielectric liquid and the built up to the machined surface was also closely related to the forms of discharges.…”

A comprehensive review on metallic implant biomaterials and their subtractive manufacturing

“…The modification on a PM-EDMed surface can be evidenced in the form of a noticeably thick recast layer exhibiting upgraded surface properties such as improved surface integrity, micro-cracks, corrosion resistance, wear resistance, and biocompatibility [ 214 , 215 ]. In the case of PM-EDM of Ti and Ti alloys, B 4 C [ 216 ], surfactant, graphite, TiO 2 [ 217 , 218 ], SiC, Al 2 O 3 [ 219 – 222 ], Si [ 223 ], and carbon nanotubes (CNTs) [ 224 ] powder particles were primarily used. For instance, with variation in the powder characteristics (particle sizes and concentrations) of SiC and Al 2 O 3 powders and dielectric mediums (such as EDM oil, deionized water, and tap water), considerable changes in the surface roughness (SR), recast layer thickness (RLT), material subtraction/removal rate (MRR), and tool wear rate (TWR) were witnessed [ 225 – 227 ].…”

State of the art in powder-mixed electric discharge machining: A review

“…Yasar and Ekmekci 114 observed many small pits within the crater with a decrease in pulse time. At high pulse times, the initial discharge pushes the powder particles outward and forms a clearer space at its center.…”