High-temperature tribology of AA7075-TiB₂/AlN composites: experiments, response-surface optimisation, and interpretable machine learning

This work develops a hybrid design and analysis strategy to improve the dry sliding wear resistance of ultrasonically processed AA7075 composites reinforced with in-situ formed Al₃Ti and TiB₂ particulates. Experimental measurements are combined with Response Surface Methodology (RSM) to optimise reinforcement levels and sliding conditions for minimum wear rate and friction coefficient. A machine-learning prediction model is also established to estimate the tribological behaviour with high generalisation accuracy, verified by a prediction deviation of < 5% for both wear and friction responses. Furthermore, Shapley Additive Explanations (SHAP) are employed to identify the dominant process–response relationships, consistently revealing temperature as the most influential parameter governing wear behaviour, followed by applied load, while sliding speed exhibits a secondary effect. The integrated approach validates the robustness of the reinforcement route, offers reduced experimental cost, and provides deeper mechanistic insight into the wear behaviour of AA7075-based hybrid composites. Highlights