Performance Evaluation of T6 Heat-Treated AA6061- Hybrid Nanocomposite Cam versus Actual Chilled Cast-Iron Automotive Cam

Abstract

This study presents the fabrication and performance evaluation of a lightweight camshaft manufactured using a T6 heat-treated aluminium metal matrix hybrid nanocomposite (AMMHNC) based on AA6061 alloy, reinforced with 2 wt.% boron carbide (B₄C) and 2 wt.% graphite (Gr). To address common challenges such as nanoparticle agglomeration and porosity, a novel integrated stir–ultrasonic–squeeze casting technique was employed, ensuring uniform dispersion and enhanced interfacial bonding. The composite underwent T6 heat treatment to improve microstructural refinement and precipitation hardening. Comprehensive mechanical and tribological evaluations revealed significant improvements in hardness (79.43 BHN), tensile strength, and wear resistance compared to the as-cast and non-heat-treated counterparts. Microstructural analysis confirmed fine equiaxed grains and preferential reinforcement accumulation along grain boundaries, contributing to grain boundary strengthening and dislocation pinning. Functional performance was validated by benchmarking the fabricated AMMHNC camshaft against an OEM chilled cast iron camshaft used in Maruti Suzuki Swift. The T6-treated composite cam exhibited comparable wear resistance while offering a ∼60% reduction in component weight, demonstrating its viability as a durable and energy-efficient alternative for automotive applications. This research establishes a promising pathway for integrating AMMHNCs in dynamic engine components, with implications for improved fuel economy and material sustainability.