Experimental investigation of wire EDM on squeeze cast Al6351/Gr/SiC hybrid metal matrix composites: A Taguchi–GRA-based optimization framework

This study aims to optimize process parameters in Wire Electrical Discharge Machining (WEDM) for a hybrid Metal Matrix Composite (MMC) composed of aluminum alloy (Al 6351) reinforced with 6% graphite (Gr) and 4% silicon carbide (SiC). The MMC was fabricated using the squeeze casting technique, and an L27 orthogonal array was employed for experimental design. Key WEDM parameters, including pulse-on time (P), pulse-off time (Q), wire feed (R), spark voltage (S), and wire tension (T), were systematically varied to assess their impact on surface roughness (SR), material removal rate (MRR), dimensional deviation (DD), and kerf (K). Gray relational analysis was utilized to determine optimal parameter settings based on the gray relational grade, while Fisher analysis of variance was conducted to evaluate the significance of individual parameters. A confirmation test validated the findings, revealing that the optimized parameter setting (P3Q1R3S1T3) significantly improved MRR, SR, and overall machining performance compared to the initial setting (P1Q1R1S1T1). Although minor variations were observed in DD and kerf, the optimization approach effectively enhanced key performance metrics. In addition, scanning electron microscopy and x-ray diffraction analyses were conducted to further characterize the machined surfaces. This study provides a systematic approach to improving WEDM efficiency for advanced MMCs, contributing to enhanced precision and performance in industrial applications.