The Development of High Strength and Ductility in High-Pressure Die-Cast Al-Si-Mg Alloys from Secondary Sources

The current article describes the results of a study aimed at developing new compositions of Al-Si-Mg high-pressure die-cast alloys, which display improved ductility in as-cast and heat-treated conditions. Studies of the new alloys, which contain higher than normal Mn contents and lower than normal Fe contents, have shown that compositions generated through the use of recycled wheels made from A356 alloy (“Troma”) may achieve the goals. As-cast, T4 and T6 heat-treated high-pressure die cast compositions have been evaluated. T4 and some T6 tempers are shown to produce an optimal combination of 0.2% proof stress, tensile strength and elongation. Some compositions also require a significantly reduced temperature of solution treatment to generate excellent combinations of mechanical properties. The alloys developed can be considered for structural die castings in modern automotive applications.