Effect of cooling rate on the solidification behaviour of Al–Fe–Si alloys

The effect of cooling rate on the solidification microstructure of an Al–Fe–Si alloy is investigated. Samples were solidified with cooling rates between 0.04 and 3.5 K s−1. The microstructures are characterised in terms of eutectic volume fraction, dendrite arm spacing and size and shape of secondary phases. Eutectic volume fraction and dendrite arm spacing were also calculated using a microsegregation model. Predicted data are found to be in good agreement with the experimental observations. Further, the role of microsegregation on phase selection is discussed with reference to earlier studies on phase selection in these alloys. The concentration of the liquid at the onset of eutectic solidification is correlated with the selection of the secondary phases in the eutectic.