Investigation on Electrical Discharge Machining Parameters of Aluminium7075/Boron Carbide/Titanium Diboride Hybrid Composites by Grey Relational Analysis

In this study, electrical discharge machining (EDM) was performed on aluminum 7075 reinforced with boron carbide (9 wt%) and titanium diboride (3 wt%) materials. The composites were manufactured via a stir-casting process. The experiments were planned according to the Taguchi design of experiments, and analysis of variance (ANOVA) was used to study the effect of the output parameters on the input parameters. Scanning electron microscopy was used to study the machinability characteristics of the machined surfaces. Finally, the output was optimized using grey relational analysis (GRA), and a confirmation test was conducted to validate the results. The results revealed that the optimal process parameters were input current (IP) = 3 A, pulse-on-time (Ton) = 75 μs, and gap voltage (V) = 50 V. Confirmation experiments corroborated the effectiveness of the GRA-optimized parameters, yielding an enhancement of GRG (grey relational grade) values. Current (IP) emerged as the most significant parameter, contributing 79.45% to the variance, followed by Ton at 8.23% and gap voltage at 4.06%. It was observed that surfaces machined under the optimal process parameters exhibited minimal unevenness compared to surfaces machined under initial and higher-level conditions.