Multi-criteria optimisation of mechanical properties in Al-SiC-MoS2 hybrid composites using MCDM methods

Aluminium based hybrid metal matrix composites (HMMCs) are extensively utilised in modern engineering applications due to their strength-to-weight ratios. This study presents a multi-criteria decision making (MCDM) approach to optimise the processing parameters. In this study, we have considered parameters of fabricated aluminium 6061-based hybrid metal matrix composites reinforced with silicon carbide (SiC) and molybdenum disulfide (MoS2) using the stir-casting technique. The mechanical performance of the developed composites is evaluated by considering key parameters such as hardness and ultimate tensile strength (UTS), providing insight into the structural integrity and load-bearing capacity. In this study, eight alternative materials A1-A8 consisting of Al 6061/SiC/MoS2 with different reinforcement variations are considered as candidate materials, and MC DM methods are applied to determine the optimal composite. The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) decision methods are employed to rank the alternatives for the composite formulations. The entropy weight method is applied to determine objective criterion weights. The obtained weights are incorporated into the TOPSIS and VIKOR methods to rank the alternative based on the closeness coefficient. The alternative A6 (88 wt.% Al, 10 wt.% SiC, and 2 wt.% MoS2) as the optimal formulation, exhibiting a maximal hardness of 208 HV and an ultimate tensile strength (UTS) of 194 MPa, indicating superior mechanical performance. The evaluation results indicate that alternative A6 achieves the best performance among all candidates, obtaining a TOPSIS closeness coefficient of 1.00 and a VIKOR index of 0.00, whereas alternative A3 shows the lowest performance with a TOPSIS score of 0.00 and a VIKOR value of 1.00, confirming the consistency of both decision-making approaches. The developed approach provides a systematic and reliable tool for material selection and can assist researchers in optimising aluminium based hybrid composites for advanced engineering and tribological applications.