Mechanical Properties and Microstructure of Recycled Aluminum Cast with Zinc and Copper Additions

This paper examines the effect of zinc and copper additions on the mechanical properties of recycled sand cast Al-Cu-Zn alloys. Chemical composition analyses of the samples showed that the actual composition of the base metal, Al, and the alloying elements, Cu and Zn, varied from the targeted composition. The tensile test results revealed that Cu and Zn additions have significant effect on the ultimate tensile strength (UTS), breaking strength as well as percentage elongation. Sample B displayed highest UTS, breaking strength and elongation values of about 216 N/mm(2), 168.02 N/mm(2) and 2.85 %, respectively. Impact test results also revealed that sample B have the highest impact energy of about 6.12 J, compared with 5.58 and 5.98 J for samples A and C, respectively. The Brinell hardness values of samples A, B and C are 16.7, 42.4, and 53.4 HBr, respectively. Thus, alloying Al with Cu and Zn has significantly improved the mechanical properties of the samples.