The microstructure and tensile properties of cast Al–9·5Si–0·35Mg alloy containing 1·5 wt-Fe have been studied to investigate the potential influence of beryllium (Be) on the entrained oxide films and its effects on the precipitation of Fe-rich phases from liquid metal. It was found that addition of Be has a great influence on the microstructure and reliability of the cast alloy. Beryllium changes the platelet morphology of Fe-rich phases to less harmful shapes. Meanwhile, this element reduces the entrainment of the double oxide films into the melt probably due to its effect on changing the strength of surface oxides in a manner that resists tearing. These effects, in turn, lead to an increase in mechanical properties and casting reliability of the alloy.

No abstract