MICROSTRUCTURE SELECTION MAPS FOR AL-FE ALLOYS

The solidification microstructures for Al-0.5-4 at. % Fe alloys under constrained growth conditions have been calculated using analytical mo dels of the growth kinetics of dendritic, eutectic and plane front int erface morphologies of stable and metastable phases. Laser remelting e xperiments are carried out on an Al-4 at. % Fe alloy with a low beam v elocity (10 mm/s) in order to complete previous experimental results o n the solidification microstructures obtained at intermediate growth r ates by Bridgman experiments and at high growth rates by rapid laser r esolidification. Comparison of predicted with experimentally determine d solidification microstructure maps shows satisfactory agreement in v iew of the limited knowledge of the thermophysical properties of this system. These maps are useful for the interpretation of microstructure s and phases forming under medium to high solidification rates and for the understanding and development of rapid solidification processing. Further the modelling is useful for improving available phase diagram information.