Elaboration of AlSi13 Casting Alloys modified using Directional Solidification Processing

Abstract

In order to improve the mechanical properties of Al-Si13 alloys various treatments and procedures are recommended such as modification treatment of the molten alloy. In this work, the effects of the modification of the alloy composition owing to the addition of 1 wt.% and 2 wt.% modifier composed of 40 wt.% NaCl and 45 wt.% NaF and 15 wt.% KCl, combined with the application of unidirectional solidification by means of the Bridgman type were studied on the Al-Si13alloy. Microstructural analyses revealed a decrease in the interdendritic spacing(SDAS), in particular owing 2% of the modifier prepared with a reduced pulling traction. The dendrites were preferably oriented along the pulling velocity for fairly low pulling velocity (500 μm/s). These microstructural modifications enabled an increase of both the hardness (HB) values and the impact toughness.