Dry Sliding Wear Study of Solid Lubricants and Sillimanite-Reinforced Aluminum Alloy Composites

The present research work investigates the effect of solid lubricants tin and graphite independently or combines on the wear behavior of sillimanite-reinforced aluminum matrix composites. Composites containing 10 wt.% sillimanite mineral were fabricated using the stir casting route. Further, 1 wt.% of graphite and also tin and also both added to form the new composites. Optical microscopy revealed a homogeneous distribution of tin, graphite and sillimanite mineral throughout the prepared materials. The addition of sillimanite particles to the base alloy refined the silicon morphology. Microhardness of the composites revealed a good interfacial bonding of sillimanite particles with the base alloy. Further, the addition of sillimanite particles and lubricating agents decreased the wear rate and coefficient of friction of the composites. Maximum reduction in wear rate and coefficient of friction was observed for sillimanite-reinforced composites with both tin and graphite as lubrication agents. For industrial sustainability, the wear property of prepared composite was also compared with the traditional brake drum material, i.e., cast iron. The wear rate of the sillimanite-reinforced composites with both tin and graphite as lubrication agents was in tune with the cast iron brake drum, which is used in the automobile industries. SEM analysis revealed that at low loads, abrasive wear was dominant, whereas, at higher loads, adhesive wear was dominant for material removal.