“Effect of Activated Carbon and Rice Husk Ash on the Mechanical and Microstructural Properties of Eco-Friendly Aluminum Hybrid Composites: An Experimental Study”

Abstract

Aluminium hybrid composites are a new generation of metal matrix composites that can meet the demands of modern engineering applications. These demands are fulfilled through improved mechanical properties, compatibility with conventional processing methods, and the possibility of reducing production cost. The performance of such composites mainly depends on selecting the right reinforcement materials, since many processing steps are linked to the properties of the particulates. In this study, aluminium was used as the base matrix and reinforced with agricultural waste–based activated carbon (AC) and rice husk ash (RHA) to produce eco‑friendly hybrid composites. The stir‑casting method was applied with different reinforcement ratios. Samples were tested for tensile strength, hardness, and impact energy following ASTM standards. Results showed that balanced addition of AC and RHA increased both yield strength and ultimate strength. The A2 sample achieved the highest tensile strength (≈145 MPa), hardness (46.6 HRB), and impact strength (13.6 J). Excessive AC or RHA reduced ductility due to particle agglomeration and stress concentration. FESEM and EDX analysis confirmed that proper reinforcement ratios led to uniform particle distribution, grain refinement, and strong interfacial bonding. These features were directly related to the improvement in mechanical properties. This study proves that AC and RHA together can produce lightweight, strong, and eco‑friendly aluminum composites. Such materials show promising applications in automobile, aerospace, and structural engineering.