Phase Evolution of -Al5FeSi During Recycling of Al-Si-Fe Alloys by Mg Melt

The recycling of aluminum materials is an important green initiative since it can avoid the need for primary metals and Al-Si-Fe is a typical scrap aluminum alloy. One key goal in recycling of Al-Si-Fe alloys is to reduce the Fe content via some techniques to separate Al and Fe. A proposed method to obtain this goal via introducing the Al-Si-Fe alloy into a Mg melt has been investigated in this work. A separation layer with gathered Fe-rich and Al-poor Fe3Al0.7Si0.3 particles was obtained at the bottom of the cooled ingot, indicating that -Al5FeSi phase evolves into Fe3Al0.7Si0.3, and quantities of Al are released to the upper Mg matrix simultaneously. However, the evolution of Al3Fe by adding binary Al-Fe alloy into Mg melt is different. It is proposed that the element Si plays an important role in the phase evolution procedure, thus affecting the performance of this method.