Solidification sequence and four-phase eutectic in AlSi6Cu4Fe2 alloy

Differential thermal analyses of an AlSi6Cu4Fe2 alloy at various cooling rates from the liquid state were performed which showed: i) possible discrepancies in the first solidification steps and; ii) solidification ending with multiple peaks at low cooling rate. Metallographic observation of the samples gave hint for understanding the discrepancies while the presence of rounded multi-phase pools – or so-called rosettes - entrapped within dendrite arms explained the multiple peaks because they solidified independently of each other.