Microstructural investigation of tensile fractography and wear properties of scrap aluminium engine head (SAEH) reinforced with fresh and spent catalysts from petrochemical industries using stir casting method

This research aims to investigate the microstructural properties, tensile fractography, and wear characteristics of scrap aluminum engine head (SAEH) composites reinforced with fresh alumina catalysts (FAC) and spent alumina catalysts (SAC) derived from petrochemical industries. Utilizing the stir casting method, four composite variants were fabricated: SAEH + SAC, SAEH + FAC, LM25 + SAC, and LM25 + FAC. The materials were characterized through scanning electron microscopic (SEM) analysis, and the composition of FAC and SAC was detailed. The investigation delves into the wear properties through pin-on-disk tests conducted at different conditions. Tensile strength results revealed distinctive performance: SAEH + FAC = 208 MPa, SAEH + SAC = 217 MPa, LM25 + FAC = 92 MPa, and LM25 + SAC = 184 MPa. Fractography analysis provided insights into the fracture behavior, showcasing the influence of agglomerates, non-coherent interfaces, lack of wetting, grain refinement, and the presence of oxides. The wear behavior, evaluated under varying operating conditions, demonstrated that wear rates increased with escalating conditions and were generally higher for LM25-based composites than for SAEH-based composites. This study introduces the innovative use of SAC in composites, offers a comparative analysis between different materials, and provides a comprehensive understanding of wear behavior under diverse conditions, contributing to the advancement of metal matrix composites.