The solidification sequence and microstructure development of secondary EN AC 46100 alloy

The main challenges in the production and utilization of secondary aluminum alloys are achieving the targeted chemical composition and controlling the level of impurity elements. Those challenges originate from the accumulation of trump elements such as silicone, magnesium, nickel, zinc, lead, chromium, iron, copper, vanadium, and manganese during recycling. The inability to achieve targeted chemical composition negatively impacts the secondary alloy properties and hinders its use in the safety-critical applications. Despite the fact that there are a variety of solutions to lower the negative impact of trump elements, each of them represents a trade-off between the coast and the recycling potential. The research was performed to estimate the influence of excess Mg and Zn on solidification sequence and microstructure development of secondary EN AC 46100 alloy. The investigation comprehended determination of chemical composition, equilibrium and non- equilibrium solidification sequence using Thermo- Calc software support as well as metallographic analysis. Based on the obtained results, it was concluded that the excess amounts of magnesium and zing led to the solidification and precipitation of complex phases, mainly Q-Al5Cu2Mg8Si7, π- Al8FeMg3Si6 and Al5(Cu, Zn)6Mg2 that are not characteristic for EN AC 46100 type alloy