Mechanical properties in as-cast and heat treated Al-Si-Cu alloys

摘要

The mechanical properties of a series of experimental aluminium castings alloys were studied in samples cut from ingots that solidified with a strong thermal gradient to obtain a wide range of microstructures. The samples were cast with a content of silicon that varied from 5% to 11% and iron from 0.3% to 0.8%, copper, manganese and magnesium were kept within the ranges of 3.1% to 3.5%, 0.40% to 0.45% and 0.27% and 0.32% respectively. Samples with different microstructures were machined into tensile specimens that were tested in the as-cast and stabilisation heat treatment conditions. The analyses show that the mechanical properties are affected by microstructural refining and to the amount of silicon added, although the former exerts a higher influence. It was also found that heat treating enhances the yield and tensile strength, but reduces the ductility of the material. No significant effect between the mechanical properties and the amount of iron was found.