Optimization of Wire-EDM Process Parameters for Al-Mg-0.6Si-0.35Fe/15%RHA/5%Cu Hybrid Metal Matrix Composite Using TOPSIS: Processing and Characterizations

Abstract

The current experimental study concerns obtaining the optimal set of wire-EDM processing factors for a novel Al-Mg-0.6Si-0.35Fe/15%RHA/5%Cu hybrid aluminum matrix composite. The composite exhibits hardness of 64.2 HRB, tensile strength 104.6 MPa, impact energy 4.8 joules, when tested using standard testing techniques. For this, composite is formulated with the help of a stir casting route. The tests are conducted as per Taguchi’s L27 OA, to explore the influence of processing factors on the surface roughness (Ra), radial overcut (ROC) and material removal rate (MRR). The optimization is executed using the Taguchi approach, followed by multiple objective optimizations with TOPSIS (one of the MADM techniques). For optimal values of Ra, MRR and ROC, the optimum set of input variables is suggested as 150 A of current, 125 μs of pulse duration, 50 μs of pulse interval and 8 mm/min of wire feed-rate. Predicted performance index value was calculated and was compared with the experiment value. It has been observed that both values are very close to each other with only 1.33% error, which means the results are validated. ANOVA confirms that current is a predominant factor influencing response characteristic parameters, which contributes 24.09%, followed by pulse duration (16.78%) and pulse interval (15.18%). The surface characterization using a scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive spectroscope (EDS) and optical microscope (OM) has also been carried out to affirm the existence of the reinforcing particles in the base matrix.