Microstructure of an Al-Fe alloy produced by unidirectional solidification

In relation to the production of composite materials, the present paper studied the influence of the solidification rate on the microstructure of an unidirectionally solidified eutectic Al-Fe alloy. The results obtained are as follows:(1) When the solidification rate was less than 10cm/hr, FeAl3 rods were regularly aligned parallel to the solidification direction. However, when the solidification rate was more then 20cm/hr, the microstructure became irregular, as observed in the normal cast structure.(2) The eutectic compounds under high and low solidification rate were rods and flakes in shape, respectively. It was found that the rod diameter decreased as the solidification rate increased.(3) The interrod spacing, λ, was related to the solidification rate, R, as λ2R=K, where K was 2.7×10-9cm3/sec.