Enhanced mechanical and wear properties of aluminium-based composites reinforced with a unique blend of granite particles and boron carbide for sustainable material recycling

In this study, a two-step stir casting technique was employed to fabricate composites using scrap aluminium cans (SAC) as matrix and a unique blend of Granite Particles (GP) and boron carbide (B4C) as reinforcements. Mono and hybrid composites were developed to evaluate the effects of the GP-B4C on the microstructure, mechanical properties, wear characteristics, and fracture behaviour of the composites. The microstructural characterization of the composites revealed that the incorporation of reinforcement into the aluminium matrix led to a refined grain structure with distinct interfaces. Both mono and hybrid composites exhibited improved hardness, with the hybrid composite showing a significant increase of 15.74 % in macro hardness and 16.33 % in microhardness compared to the base material. The mono composite demonstrates the highest ultimate tensile strength of 218 MPa, followed by the hybrid composite with a strength of 192 MPa. The improved mechanical properties of the mono composite are attributed to the reduction in grain size and the enhanced interfacial bonding between the reinforcement and the matrix. Although the hybrid composite exhibited more porosities, it shows the maximum ultimate compressive strength of 1124 MPa. The tensile fractured surfaces displayed dimples, cleavage facets, transgranular cracks, and river line markings. The wear loss of the mono composite decreased by 11.2 %, while that of the hybrid composite decreased by an impressive 28 % compared to their parent base matrix. The worn surface exhibits a combination of abrasive, adhesive, and delamination wear mechanisms.