Heat treatment optimisation of secondary AlSi10MnMg(Fe) test parts fabricated by vacuum assisted high pressure die casting technology

Primary AlSi10MnMg alloy is the most widely used alloy for manufacturig of vacuum assisted high pressure die castings (VPDC) with high ductility requirements. However, the use of secondary alloys offers several advantages such as cheaper raw material, less energy consumption during its manufacturing and protection of resources. But, the higher amoun of Fe, a ommon impurity in secondary alloys, reduces the ductility due to the formation of needle/olatelet shaped β-Al5FeSi phase. These phases can be transformed into less harmful Chinese secript α- iron phases by appropriate microadditions on Mn.

In this works a secondary type alloy with 0.60 %Fe with optimized Mn content, has been cast in test parts with different conditions: F (as-cast), T4, T5, T6, T7 temper. The solution temperature and time have been optimized regarding the formation of internal prosity and blisters. The results show that mechanical properties comparable to the corresponding primary alloy can be obtained when the parts are properly heat treated and free of casting defects and the fraction of porosity is low.