Optimisation of coconut shell particles reinforced Al-7075 aluminum composites with B₄C and ZrO₂ using CRITIC-EDAS for tribological performance

This study optimised and evaluated the tribological performance of hybrid Al-7075-T6 composites reinforced with coconut shell particles (CSP), boron carbide (B₄C), and zirconia (ZrO₂) using the CRITIC-EDAS method. The effects of varying the weight percentages of CSP (0–4 wt. %) with B₄C (3 wt. %), and ZrO₂ (3 wt. %) as constant, on wear rate and coefficient of friction (COF) were investigated at different temperatures (Room temperature – 25, 150, 200 to 250°C). Results showed ZrO₂ based configurations, particularly Z7 (ZrO₂, 2 wt. % CSP, 250°C), outperformed B₄C based composites in wear resistance and COF under high thermal conditions. Z7 achieved an EDAS score of 0.812, representing an improvement of 14.04% over B10 (B₄C, 3 wt. % CSP, 200°C). This performance is attributed to ZrO2’s transformation toughening mechanism and thermal stability at elevated temperatures. Sensitivity analysis confirmed Z7 and Z11 as top performers across varying criteria weights. CSP integration enhances tribological properties while supporting sustainable manufacturing. This study paves the way for the development of next-generation hybrid MMCs for aerospace, automotive, and defense industries, particularly in landing gear bushings, actuator sleeves, control surface bearings, engine cylinder liners, brake rotors, and turbine casings.