EDM machining effectiveness for Ti–6Al–4V alloy using Cu–TiB2 ceramic composite electrode: a parametric evaluation

Abstract

The study addresses the requirement for better machining of titanium alloy (Ti–6Al–4V) in Electrical Discharge Machining (EDM) with a Cu–TiB2 ceramic composite powder metallurgy electrode. The electrode underwent analysis for relative density, hardness, and microstructure using field emission scanning electron microscopy and X-ray diffraction. Results indicated a relative density of approximately 90.08%, a microhardness of around 142 H V, and an electrical conductivity of 46% IACS. Response Surface Methodology (RSM) was used as Design of Experiment (DoE) technique for this study to investigate the effects of pulse current (Ip), pulse on time (Ton), and discharge voltage (V) on Material Removal Rate (MRR) and Surface Roughness (SR). Analysis of variance (ANNOVA) at a 5% significance level highlights the significant impact of Ip, Ton & V, and the interaction between selected parameter on MRR and SR. Results show a significant influence of pulse current (Ip) and pulse duration (Ton) on both MRR and SR. Rising pulse current correlates with improved MRR, with optimal parameters identified as a pulse current of 15 A, a pulse on time of 150 μs, and a voltage of 50 V. The study also looks into the usage of reverse polarity to improve surface finish compared to typical EDM methods. The use of Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) analyses adds depth to the evaluation of surface formations on the workpiece. EDS analysis indicates the presence of 63.13 wt (%) of boron on the machined work surface, affirming the effectiveness of the developed Cu–TiB2 electrode in machining titanium alloy.