RSM-VIKOR Based Optimization of Machining Parameters for Improved Surface Integrity of HEAs

This work employed Response Surface Methodology (RSM) with the VIKOR multi-criteria decision-making model to investigate the machining performance of the high-entropy alloy (HEA) in ECM method. Three electrolyte systems were employed such as sodium nitrate (NaNO3), sodium chloride (NaCl) and NaNO3/NaCl mixed electrolyte. The tests were conducted by varying the feed rate (0.4–0.6 mm/min) and electrolyte concentration (100–200 g/L). The MRR model was found to be significant (p = 0.03814) by most significant parameters, electrolyte type and concentration. Feed rate (p = 0.03166) and electrolyte type (p = 0.01301) also influenced surface roughness respectively. Perturbation analysis has shown that the type of electrolyte is the most influential factor for increasing MRR and reducing SR. Multi-objective optimization using the RSM-VIKOR method identified the optimal factors at EC = 100 g/L, mixed electrolyte (NaNO3 + NaCl), and feed rate of 0.5 mm/min, yielding a high MRR of 67.3 rnmVmin and a minimum SR of 1.26 μm. The results demonstrate the effectiveness of the hybrid RSM-VIKOR approach in resolving performance and enhancing ECM efficiency for HEAs.