Polymeric nanocomposites have been extensively investigated due to their potential for enhancing the mechanical and tribological properties of polymer composites. In this study, the mechanical performance of carbon fiber-reinforced epoxy composites modified with nano-sized ferrochrome slag particles, an industrial by-product from stainless steel manufacturing, was evaluated. Composite laminates were fabricated using a vacuum-assisted hand lay-up process, with consistent carbon fiber reinforcement and uniformly dispersed nanofillers in the epoxy matrix. Mechanical properties such as tensile, flexural, impact, and Shore D hardness were evaluated as per ASTM and ISO standards. At 2 wt.% nanofiller loading, enhanced tensile strength and hardness by 33.02% and 8.92%, respectively, were achieved, while flexural strength and impact strength increased by 3.70% and 3.62% at 1 wt.% compared to the neat composite. Higher filler contents (>3 wt.%) resulted in reduced performance due to particle agglomeration and microstructural inhomogeneity. A scanning electron microscope was used to determine the uniform dispersion and agglomeration of nanofillers. The results demonstrated the potential of ferrochrome slag as a sustainable and cost-effective nanofiller for advanced composite applications.

Due to the increasing demand for sustainable and lightweight materials in the automotive sector, there has been a renewed interest in natural fiber-reinforced polymer composites. In this work, the mechanical behaviour of hybrid composites composed of banana, kenaf, and coir fibers reinforced with high-density polyethylene (HDPE) containing nano-fillers is examined. The composite was prepared with 70% epoxy resin. The contents of fibers and HDPE were varied in three different proportions: (1) 10% banana, 10% kenaf, 5% coir and 5% HDPE; (2) 7.5% banana, 10% kenaf, 7.5% coir and 5% HDPE; and (3) 7.5% banana, 7.5% kenaf, 10% coir and 5% HDPE. Nanoparticles were incorporated into the HDPE matrix to enhance the mechanical and physical characteristics of the composites. Experimental results showed that compositions with higher banana and kenaf fiber contents exhibited improved tensile strength, compressive strength, and impact resistance. Conversely, formulations containing a higher coir fiber content exhibited enhanced flexural strength, hardness, and water absorption performance. Scanning electron microscopy (SEM) analysis of fracture surfaces provided insights into fiber–matrix adhesion and fracture mechanism. Overall, the incorporation of nano-fillers significantly improved the behaviour of hybrid natural fiber/HDPE composites, making them suitable for lightweight and eco-friendly automotive components. These enhanced mechanical properties demonstrate the strong potential of the developed hybrid nano-filled composites for lightweight automotive components, contributing to vehicle weight reduction, improved fuel efficiency, and lower emissions.