Comparative Characterisation of Aluminium Bars Produced from Discarded Aluminium Parts
Segun Damilare Adedokun
*
Department of Mechanical Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria and Department of Mechanical Engineering Technology, The Federal Polytechnic, Ede, Nigeria.
Emmanuel Foluwaso Alagbe
Department of Mechanical Engineering Technology, The Federal Polytechnic, Ede, Nigeria and Department of Mechanical Engineering, Federal University Oye-Ekiti, Ekiti State, Nigeria.
Grace Olayemi Ayemonisan
Department of Mechanical Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
This research explores the mechanical and microstructural properties of aluminium bars made from discarded automotive, construction, and household materials. Samples: Ford gearbox casing (AGBC), Maltina cans (AMC), Tower long-span roofing sheets (ARS) and 33 kV overhead line cables (AHVC) were remelted and recast using the sand moulding method. The tests of hardness and impact were performed depending on ASTM E10 and ASTM E23, respectively. There was a significant difference in mechanical behaviour: AGBC had the highest Brinell hardness (382.39 +/- 3.12 BHN) and lowest impact energy (20.40 +/- 0.61 J), and AHVC had the best toughness (65.01 +/- 0.52 J) and moderate hardness (137.79 +/- 2.11 BHN). Analysis of the SEM indicated that porosity and Si- and Fe-rich intermetallics were the causes of the strength-ductility trade-offs in the samples. It is concluded that in recycled aluminium, alloy composition and solidification control are the determining factors in performance. These results offer a strategic framework in the selection and improvement of aluminium scrap towards specific industrial applications, including automotive, building construction, lightweight structural parts, etc.
Keywords: Aluminium recycling, mechanical properties, microstructure, impact strength, sustainability