Experimental and data-driven investigation of dry sliding wear behaviour in Al 6061–graphite composites

Aluminium alloy 6061 is widely used in engineering because of its good strength-to-weight ratio and corrosion resistance, but its wear resistance under dry sliding is limited. In this study, Al 6061–graphite composites containing 0, 6, 8, and 10 wt.% graphite were fabricated by stir casting. Their tribological behaviour was examined using a pin-on-disc tribometer under loads of 9.81, 29.45, and 49.05 N. The results showed a non-monotonic wear response with load: wear increased initially up to 29.45 N and then decreased at 49.05 N, which was attributed to the formation of a graphite-rich tribo-layer. The wear rate ranged from about 2.1 to 3.5 mm³/m, while the coefficient of friction varied from 0.32 to 0.58 and generally decreased with increasing graphite content. To predict wear behaviour, linear, quadratic, cubic, support vector regression, and random forest models were assessed using the experimental dataset. Among them, cubic regression gave the best performance for the limited data available, with R² of about 0.60 and the lowest LOOCV RMSE. The modelling results are interpreted cautiously because of the small dataset and are intended mainly for trend analysis within the studied range.