Development of Automotive and Marine Appliable Aluminium Composite by Utilizing Agro-Waste Material as Performance Enhancement Particles

Abstract

Aluminium-based materials are lightweight materials used for producing automotive and aircraft components. However, aluminium materials diminish in performance on exposure to degrading environments, which limits their areas of usage and applications. The degrading effect results in poor resistance to wear and corrosion, reduced properties and defective microstructure. In this work, 6063 aluminium alloy was reinforced with particles of agricultural waste (walnut shell) to produce six samples with five samples of reinforced and a control (unreinforced) sample. Each of the samples of the reinforced alloy was moulded into a 25 mm diameter by 130 mm height using the stir casting method using an industrial pit furnace. The samples were thereafter machined to a diameter of 20 mm and cut into a thickness of 10 mm for characterizations. The potentiodynamic polarization method was used to test for the samples’ corrosion resistance properties following the ASTM G102 standard in 3.65% NaCl test medium. The hardness property was investigated using the Brinell hardness machine following the ASTM A-370 standard, while the microstructure and crystallographic phase studies were carried out using SEM/EDS and XRD profiles, respectively. The unreinforced 6063 Al alloy sample exhibited the highest corrosion rate (Cr) of 0.7321 mm/year and the lowest hardness of 104.94 kgf/mm2. The 10% wt. walnut shell particles (WSP) reinforced 6063 Al alloy sample exhibited the lowest corrosion rate (Cr) of 0.1336 mm/year and the highest hardness of 109.24 kgf/mm2. This indicated that the walnut shell particles enhanced the corrosion and indentation resistance of the alloy. In addition, the SEM images indicated that the agricultural waste (walnut shell particles) reinforced samples exhibited more refined microstructure, lower porosity and smoother morphology compared to the unreinforced (control) sample. Also, the XRD profile of samples revealed some high peak intensity crystallites such as Al(ZnS), Al2O3 and (FeMn)SiO2. These high peak intensity crystallites indicated that these reinforced samples possessed chemical and microstructural homogeneity, high stability and good surface texture.