Dimensional stability analysis in Al-Si alloys

In this paper dimensional stability investigation in two hypoeutectic composition is proposed. Specifically, the study of some samples in AlSi7Mg0,3 and AlSi8,5Cu3,5 alloys is realized and a comparison of the obtained data will be discussed. Starting from dilatometric analysis the dimensional modification of the alloys is monitored. For both materials analysis has been conducted by heating to 500°C at various heating rates and determining the activation energy for the decomposition process of the supersaturated solid solution. The morphological characterization of the alloys is performed at equilibrium in a metastable state by means of optical and scanning electron microscopy. The evaluation of structural changes in the alloys was confirmed by microhardness measurements.