Tribo-mechanical characterisation of self-lubricating aluminium based hybrid metal matrix composite fabricated via powder metallurgy

In this research, the tribo-mechanical behaviour of self-lubricating aluminium (Al) based hybrid metal matrix composites (MMCs) reinforced with graphite (Gr) and Al₂O₃ particles (Al+Gr+Al₂O₃) were studied aiming to obtain the superior wear and mechanical properties in a single material. Three different compositions of hybrid MMCs were fabricated by powder metallurgy technique, their wear and mechanical properties were tested and compared with pure Al and Al+Gr composite. The microstructure of the samples was examined and various mechanical properties such as microhardness, tensile and flexural strength were evaluated. The wear behaviour of the hybrid MMCs was investigated by using a pin-on-disc tribometer. The results revealed that the combined effect of Al₂O₃ and graphite reinforcement particles significantly improved the wear and mechanical properties of hybrid MMCs. All the mechanical properties were increased and the wear rate and coefficient of friction were decreased remarkably. Besides, the reinforcement composition of 3%Gr and 10%Al₂O₃ (Al+3%Gr+10%Al₂O₃) forms a smooth tribosurface thus increases the wear-resistant properties at the highest level than that of other compositions of the hybrid MMCs.