Modification of Al-Si12 alloy with metalic sodium

MODIFICATION OF A1-Sİİ2 ALLOY WITH METALIC SODIUM (M.Sc. Thesis) Kadir KOCATEPE GAZI UNIVERSITY INSTITUTE OF SCIENCE AND TECHNOLOGY September 1988 ABSTRACT Modification of A1-Sİİ2 alloy by additions of metalic sodium that are widely used numerous in applications, has been studied in this M.Sc. thesis. The refinement and homogenousl distribution of the coarse plate form of Si phase, have been aimed to show by shift of eutectic undercooling temperature and micro structure. In this experiment, alloy of A1-Sİİ2 was melted and then degassed with NaCl. Different quantity of metalic sodium were added to the alloys at different temperature. The alloy was held that at the different of holding time and poured in the sand mould. Cooling curves and micro structures of solidified alloys in the sand mould were observed, after that, optimum quantity of metalic sodium, temperature of additions and holding time were determined for modification of A1-Sİİ2 alloy. As a result, the mechanical properties of A1-Sİİ2 alloy was improved by additions metalic sodium. Ill