In foundries and aluminium industry, recycle materials are used for higher efficiency and better productivity of process. In this study, the influence of returns and scrap parts on the quality of AlSi9Cu3 castings was examined. The effects of different amounts of returns and scrap parts on the mechanical properties were observed, e.g. hardness and tensile test.
First, the cooling curves were recorded by using Thermal Analysis (TA). Later, we analyzed them and determined the characteristic temperatures from the solidification process. To confirm the formation of phases during solidification, Differential Scanning Calorimetry (DSC) analysis was also used.
For better understanding of the effects, microstructures were analyzed and observed using Light Optical Microscopy (LOM) and Scanning Electron Microscopy (SEM). By increasing the amount of recycled material, different amounts of phases were formed in the microstructure. In addition, these formed phases were analyzed by using EDS detector. Two iron rich phases occur; less harmful α-Al15(Mn,Fe)3Si2 phase has a »Chinese script« morphology and second β-Al5FeSi phase with needle-like shape. Amount of α-Al15(Mn,Fe)3Si2 phase decreases with addition of return material due to a decrease in the Mn/Fe ratio. The tensile test showed that the yield strength and ultimate tensile strength decreases as the amount of return material increases, elongation is slightly higher. The amount of phases was increased with a higher percentage of return material.
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