Utilization of Used Aluminum Beverage Cans and Ultrasonic Melt Processing for Improving Microstructure and Properties of Hypereutectic Al-Fe Alloy

The objective of this research was to investigate the effect of used aluminum beverage cans addition and ultrasonic melt processing (USP) on the microstructure and properties of hypereutectic Al-Fe alloy. This study focused on the investigation of Al-4Fe alloy and the addition of 50wt% aluminum cans. The results revealed that the chemical composition of alloying elements Mg, Mn, Si, and Cu increased when aluminum beverage cans were added to the binary Al-4Fe alloy, leading to a more complex microstructure with elongated primary intermetallic phases and variously dispersed small phases within the aluminum matrix. The presence of intermetallic phases tended to form phases such as Al3(Fe, Mn), Al6(Fe, Mn), Al8Fe2Si, and Mg2Si. Additionally, the eutectic and dendrites were found to be more refined, and the macrostructural features revealed finer eutectic colony (grain) sizes with aluminum beverage cans addition. Moreover, USP treatment reduced the size and improved the dispersion of intermetallic phases, as well as refining the eutectic colony structure, leading to a more equiaxed microstructure. This structural refinement resulted in higher hardness values for Al-4Fe-50% scrap compared to Al-4Fe (44 HB versus 32 HB), further increasing after USP treatment. However, the electrical conductivity of the alloy decreased when aluminum beverage cans were added or after USP treatment, but properties can be enhanced by aging at appropriate temperatures. After aging, the hardness of the Al-4Fe alloy in all conditions increased, along with an increase in electrical conductivity.