Machining and Parametric Optimization of Lanthanum Oxide and Aluminium Oxide Reinforced Metal Matrix Composites: A Comparative Study using VIKOR and COPRAS MCDM Techniques

Abstract Aluminium metal matrix composites (AMMCs) are emerging as promising substitute materials in various production sectors to meet the current technological demands for lightweight materials with improved strength, hardness, stiffness, wear, and corrosion resistance qualities. Because of their better physical and wear resistance qualities, hybrid Al-MMCs with heterogeneous reinforcing elements are gradually replacing single-reinforced composites. In the present work, using a stir-casting process, hybrid AMMCs have been developed by incorporating rare earth elements La₂O₃ and Al₂O₃ as reinforcements in Al 6063 alloy. The developed composite showed a homogeneous distribution of the incorporated reinforcements as observed from SEM and XRD characterization. Further, an attempt has been made to optimize the input process parameters like speed (rpm), feed (mm/min.), and depth of cut (mm) for maximum material removal rate M.R.R. (mm³/min.) and minimum surface roughness Ra (µm) in traditional milling operation. The L₉ Taguchi orthogonal array was used to plan out the experiment. The optimum M.R.R. and Ra were identified based on the Mean Effect and Signal-to-Noise ratio plot. Furthermore, MCDM techniques like VIKOR and COPRAS were also used with three different subjective weight allocation strategies to identify the compromise optimal among the nine experimental runs. The spindle speed of 900 rpm, feed rate of 50 mm/min, and depth of cut of 0.9 mm resulted in the best compromise of maximizing MRR while minimizing the Ra.