Evaluation of Tribological Performance for Aluminium Metal Matrix Composites: Entropy-VIKOR MCDM Approach

Abstract

Aluminium Hybrid Metal Matrix Composites (AHMMCs) are increasingly used in aerospace, automotive, and marine applications because of their superior mechanical and tribological properties. This study investigates Al6061-based hybrid composites reinforced with equal proportions of SiC and Al₂O₃, with the total reinforcement content varied from 0-12 wt.%. The composites were fabricated using ultrasonic-assisted stir casting with a bottom-pouring arrangement. Their tribological performance was evaluated using a sliding wear and friction tribometer under varying reinforcement contents, normal loads, sliding velocities, and sliding distances. A Taguchi L27 orthogonal array was employed for experimental design, while volume wear loss (V), wear rate (WR), and coefficient of friction (COF) were simultaneously optimized using Entropy-VIKOR analysis. The results indicated that increasing SiC-Al2O3 reinforcement improved the wear resistance of the composites through the formation of protective/self-lubricating tribo-layers. The optimum condition corresponded to 10 wt.% reinforcement, 50 N load, 2.5 m/s sliding velocity, and 750 m sliding distance, yielding the minimum VIKOR index (Qi). ANOVA confirmed that reinforcement content was the most influential parameter, which influenced the multiple responses. The developed hybrid composites demonstrate promising potential for tribological applications requiring enhanced wear resistance.