Design of aluminum eco-composite for sustainable engineering application by the valorization of municipal wastes: Experimental and response surface analysis

Reprocessing municipal wastes into useful engineering components is one way to reduce their environmental impact. This paper presents a report on an alternative experimental approach to reprocessing common environmental wastes like aluminum scraps, steel shavings, and coconut shells into eco-friendly engineering composite. Equally, response surface analysis was incorporated in the development and validation of predictive models fit for future prediction of response properties. Aluminum scrap was heated into a liquid state and reinforced with recycled steel particles (RSP) and coconut shell ash particles (CSP) at varying proportions. Specimen design involves three group mixes: A, B, and C. Each of the three groups mixes comprised 0, 1, and 2 % RSP at constant dosage, respectively. Meanwhile, each mix was incorporated with 4, 8, and 12 wt % CSP. The microstructural features, physical (porosity, density, and relative density), and mechanical (tensile strength, hardness, elastic modulus, fracture toughness, impact strength, and percentage ductility) properties were appraised. The outcome revealed that the combination of the two reinforcements (RSP and CSP) contributed to microstructural evolution within the specimens. The porosities of the composite specimens were reported to marginally increase with the reinforcement combination. Interestingly, the composite exhibited lighter weight with improved mechanical performance. Mathematical models derived for the response properties were certified fit for future analysis and predictions. Meanwhile, the optimization procedure revealed that the combination of 1.3 % RSP and 6.7 % CSP was suitable for the design of optimal recycled aluminum composites for sustainable engineering designs. The results clarified that the reinforcement particles (RSP and CSP) are low-cost alternatives to synthetic ceramic reinforcements in the aluminum composite."