Experimental investigation of influence of age hardening temperature and cooling medium on tribological behaviour of aluminium/tungsten carbide metal matrix composite.

This work investigates the hardness and wear resistance of an Aluminum/Tungsten carbide metal matrix composite in relation to its age-hardening temperature. The composite was fabricated by stir-casting technique, and samples were cooled in a furnace, water, and atmosphere after being aged for two hours at 0 °C, 250 °C, and 450 °C. The results showed that the composite aged at 250 °C under furnace cooling achieved a 50.48% increase in hardness compared to the non-aged composite, while those cooled under water and atmospheric conditions exhibited increases of 30.82% and 39.33%, respectively. In the investigation of the composite's wear characteristics, two variables were considered: sliding distance (1000, 1500, and 2000 m) and load (10, 20, and 30 N). The composite aged at 250 °C demonstrated a significant increase in wear resistance, attributed to high volume of precipitates formed at the grain boundaries, which reduce dislocation movement and result in reduced wear compared to other aged composites cooled under water and atmospheric conditions. The Taguchi method was used for optimization to identify conditions that minimize wear rates across various cooling environments, which were then experimentally investigated. The results revealed that low wear observed in composite aged at 250 °C, regardless of the cooling medium. For furnace-cooled samples, aged at 250 °C with a 10 N load and a 1000 m sliding distance was optimal compared to the other cooling environments and Scanning Electron Microscope (SEM) observations indicated that adhesive wear is the primary wear mechanism, with severity influenced by load, sliding distance and aging temperature.