Mechanical Properties of AlSi9Mg Alloy with a Sodium Modifier

Abstract

Al–Si alloys are among the most popular casting metals. Two-component aluminium alloys with silicon are not suitable for direct use after melting. Subject to their silicon content, Al Si alloys have a coarse-grained eutectic phase, and alloys with more than 13% Si content also feature large crystallites or β-phase needles. The β-phase is hard, but also fragile. Large crystallites are good planes of division, and they reduce the mechanical properties of alloys.In this study, the Al-9% Si alloy was refined with a sodium modifier. The modifier was added to the mould by the in-mould method. The modifier's influence on the microstructure and mechanical properties of the alloy was presented graphically. The results of the analysis indicate that the compound modifier influenced the evaluated properties of the Al-9%Si hypoeutectic alloy.