A DTA study of the solidification of Al-Si alloys

Differential thermal analysis is a quite sensitive technique to study solidification and solid-state transformations of alloys. It gives accurate estimate of the characteristic temperature of any phase changes with latent heat release or rapid heat capacity variation. This technique is applied here to the description of solidification of Al-7Si and Al-7Si-1Fe alloys. These alloys present slight but reproducible differences in the thermal arrest related to the (Al)-Si eutectic. A simple model for DTA analysis shows that the growth kinetics of the (Al)-Si eutectic is nearly linear in time for the range of cooling rates investigated