Abstract
The aim of this work was to explore changes in the solidification kinetics associated with the presence of modified and nonmodified Al-Si eutectic in Al-Si alloys, as revealed by Newton Thermal Analysis (NTA). Hypoeutectic and near eutectic Al-Si melts with different Sr contents were produced in silicon carbide crucibles. The addition of strontium to the melts was accomplished using a Al-10%Sr master alloy. The chemical composition was controlled by spark emission spectrometry. Microstructural characterization of experimental probes was performed by optical microscopy. NTA was carried out at two different cooling rate conditions using a type K thermocouple. NTA results show that an increase in Sr content produces changes in solidification rate evolution at the beginning of eutectic solidification of the experimental alloys. During the rest of solidification, both modified and unmodified eutectic show similar solidification rate evolution.

Key words
solidification kinetics, Al-Si, undercooling, eutectic modification

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