Cooling rate and microstructure of rapidly solidified Al-20 wt.% Si alloy

A 40 (mu)m thick melt-spun ribbon was manufactured by using a single roller melt-spinning technique, and the temperature distribution of the melt-spun ribbon was obtained. The solidification time and the cooling rate of the melt-spun ribbon were estimated to be 6.59 × 10^-5 s and 1.11 × 10^6 °C/s, respectively. The morphologies of primary silicon in the melt-spun ribbon were drastically changed to fine block-shape (maximum size of primary silicon is 5 (mu)m, minimum size of primary silicon is 0.5 (mu)m and average size of primary silicon is 2 (mu)m), and the smaller eutectic silicon can be obtained due to the rapid solidification.