Evaluation of the effect of castor shell particulates on the structural and mechanical properties of Al-(4.5 wt%Cu-2wt%Si-0.5 wt%Mg) composite

This study investigated the effect of castor seed shell particulates (CSSp) in particle size of 63 μm on the mechanical, structural and wear properties of Al-4.5 wt%Cu-2wt%Si-0.5 wt%Mg-based composites. The CSSp was alkali-treated to improve surface morphology, distribution, and interaction with the Al-4.5 wt%Cu-2wt%Si-0.5 wt%Mg alloy. X-ray fluorescence (XRF), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy were used to characterize the materials. The aluminum-based alloy system composites were produced using the double-layer feeding stir casting technique, with reinforcements added in loading of 3, 6, 9, 12, 15, 18, and 21 wt%. Results from characterization revealed the presence of a high percentage of CaO and traces of other metallic oxides in CSSp, which forms high-temperature compounds and also plays an important role in carbide formation in composites, thus improving mechanical properties. The mechanical properties of the composites showed improvements in ultimate tensile strength, hardness, impact, wear resistance and corrosion resistance, with a maximum tensile strength of 130.4 MPa, hardness of 49.5 BHN, impact of 47.7 J, and a lower wear rate of 2.83×10-4 mm 3 /mm. The densities of the composite sample decrease as the CSSp reinforcement is increased, with the composite sample having the lowest density value of 2.589 g/cm 3 theoretical and 2.153 g/cm 3 experimental occurring at a 21w% CSSp reinforcement value. The difference between the theoretical and experimental density values indicates the presence of porosity, which has its highest value of 2.94 at 21w% of the CSSp reinforcement. Because of its increased wettability and minimal porous structure, the CSSp-reinforced aluminum-based composite has the lowest density value. The findings led to the conclusion that CSSp is a promising plant-based reinforcing material for improving the properties of aluminum-based composites. This suggests that alkaline-treated CSSp can significantly improve the mechanical and structural properties of aluminium-based composites.