Optimization of carbonized wheat husk reinforced AA6061 composites for enhanced mechanical performance

Abstract The increasing demand for lightweight, cost-effective, and high-performance materials in the automotive industry has driven interest in aluminum matrix composites (AMMCs) reinforced with sustainable materials like agricultural waste. While some agro-waste reinforcements, such as rice husk ash, palm kernel shell ash, and coconut shell ash, have been explored, the use of carbonized wheat husk (CWH) remains relatively novel. Wheat husk, an abundantly available agro-waste often disposed of by burning, contributes to environmental pollution and greenhouse gas emissions. Its use as a reinforcement particulate will help mitigate these environmental issues. Moreover, the adoption of CWH aligns with circular economy principles and offers a sustainable pathway for producing lightweight components with improved mechanical properties. In this study, CWH-reinforced AA6061 composites were produced at varying parameters using stir casting. Taguchi’s L9 orthogonal array was employed to optimize three parameters: percentage composition (PC) of the reinforcement, melting temperature (MT) of the alloy, and stirring time (ST), with levels of 5–15 wt.%, 700 °C–800 °C, and 3–9 min, respectively. Microstructural examination of the developed AA6061–CWH composites revealed that the CWH particles were well bonded to the matrix and uniformly distributed within the continuous AA6061 matrix. Mechanical testing of the fabricated nine composite samples showed significant improvements over the control sample (unreinforced AA6061), and a confirmatory experiment validated the Taguchi-optimized parameters for AA6061–CWH composites, showing a 61.8% increase in tensile strength and a 59.8% improvement in hardness compared to the unreinforced sample. ANOVA results revealed that CWH composition was the most significant factor influencing the mechanical performance of the developed composites. This research has established the potential of carbonized wheat husk as a sustainable reinforcement material for developing cost-effective and performance-enhanced aluminum matrix composites suitable for lightweight automotive and structural applications.