Influence of Grain Refiner, Modifier and Graphene on the Dry Sliding Wear of Hypereutectic Al–Si Alloys

The present study deals with the investigation of wear behaviour of cast hypereutectic aluminium silicon alloys subjected to grain refinement and modification using grain refiners and modifiers. An analysis of the tribological properties of the graphene-reinforced Al–16Si alloy, which is simultaneously subjected to refinement and modification is also performed. Hypereutectic aluminium silicon alloys with five different compositions are casted, and a comparative analysis of their mechanical and tribological properties is performed. The hardness of the samples is measured by Vickers hardness test. The SEM and the optical microscopy of the specimens are performed. The tribological properties of the samples are investigated using the pin-on-disc wear test machine under dry sliding conditions. Impact of varying load on the wear of the casted alloys at constant sliding distance and constant velocity is performed. Similar wear test is conducted for varying sliding velocity at constant sliding distance and constant load. The tribological wear tests revealed that the rate of wear and the coefficient of friction is the minimum for the graphene reinforced Al–Si alloy which is simultaneously grain refined and modified. A gradual increase in the wear rate is observed along with the increase in the load for all the specimens. A similar trend is noticed in the wear tests conducted at varying velocity. The coefficient of friction showed a decreasing trend with the increase in the load for all the specimens in the wear test conducted under varying loading conditions.