Optimization of WEDM of a novel Al-MMC using an integrated MCDM approach

Purpose: Nowadays, machinability studies of novel aluminium metal matrix composites (Al-MMCs) have become crucial to ensure their applications in automobile, aerospace, marine, packaging, railways, construction and sports industries. Among various non-traditional machining processes, wire electrical discharge machining (WEDM) has been gaining immense importance among the researchers as a viable option for machining of those Al-MMCs. During the WEDM operation, identification of the optimal combination of its various input parameters is deemed to be crucial for having enhanced efficiency and cut quality. The purpose of this paper is to optimize WEDM operation of a novel hybrid Al-MMC using an integrated approach, fusing together CRiteria Importance Through Intercriteria Correlation (CRITIC) and Mixed Aggregation by COmprehensive Normalization Technique (MACONT). Design/methodology/approach: In this paper, a novel Al-MMC is developed using Al 6063 as the base material, and 5% SiC (silicon carbide) and 2.5% CeO2 (cerium oxide) as the reinforcements. It has a fine grain structure with reinforcements trapped around the grain boundaries resulting in higher hardness, better corrosion resistance and adequate strength properties. The developed Al-MMC is machined using a WEDM process based on a Box-Behnken design plan for cutting slits from the bulk. During the WEDM process, peak current (Ip), pulse-on time (Ton) and pulse-off time (Toff) are treated as the input parameters, while material removal rate (MRR), surface roughness (SR) and kerf width (KW) are the responses. Findings: Application of the CRITIC method helps in determining the weight of each of the responses considering the information content and randomness of the experimental data. On the other hand, the conducted experiments are ranked employing the MACONT method, developed combining three normalization procedures and two aggregation operators. It is noticed that a compromise solution of Ip = 6 A, Ton = 30 µs and Toff = 10 µs would simultaneously maximize MRR, and minimize both SR and KW values. Originality/value: Keeping in mind the immense potential of hybrid composites having more than one reinforcement in enhancing mechanical, tribological and corrosion resistance properties, in this paper, a novel Al-MMC is prepared containing CeO2 (a rare earth element) as one of the reinforcements. It is machined using the WEDM process and later optimized employing a robust integrated multi-criteria decision making tool.