Abstract

The A A 308-type alloy is one of the most widely used aluminum diecasting alloys. and it is applied in many components in the automotive industry. The aim of this work is lo investígate the solidification char­acteristics related to the precipitated phases that are formed in the modified A A 308-type alloys with the high magnesium content. The solidification process of the alloy with the present high quantity of magnesium under investigation has been followed by thermal analysis, EOS (Emission Optic Spectroscopy), and subsequently by metallographic examination of the solid samples using SEM and EDS. The considered alloy was solidified in a ceramic crucible of 35 nim diameter placed inside a resistive furnace. A thermocouples set was connected to a computer system in order to obtain the solidification characteristic curves. In our experimental system, the so­lidificaron process starts when a metallic bar made of aluminum reaches the melt at the same time when the furnace is turned off. The average cooling rale obtained was 3,7 °C/s and the typical cooling curve showed characteristics peaks that correspond to the distinct precipitates formed during the solidification of the experimental alloy.