Mechanical and microstructural property assessment of recycled Al-alloys for automotive application: A sustainable engineering solution

– The present study investigates the hardness and microstructural development of an aluminium alloy (Al–0.82%Mg–2.93%Si–0.01%Mn) fabricated through gravity die casting from sustainable aluminum by recycling scrap. The alloy’s microstructure was characterized using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis, which confirmed the formation of an α-Al matrix with uniformly distributed Mg and Si phases. Mechanical properties were evaluated by Vickers microhardness testing under varying loads to establish the indentation size effect (ISE) and by tensile testing to determine yield strength, ultimate tensile strength, and ductility. The base metal alloy exhibited a yield strength of 205.6 MPa, ultimate tensile strength of 242.3 MPa, and total elongation of 13.6%. Microhardness measurements ranged between 33–55 HV, with statistical analysis confirming the significance of load dependence. Micrograph analysis has been performed. Mechanical properties were assessed by means of microhardness studies, which also linked them to microstructural characteristics, tensile and cyclic behaviours, thereby revealing insights for optimizing cast aluminum alloys for lightweight, automotive applications.