Solidification of Undercooled Intermetallic Forming Systems

Abstract

Intermetallics exhibit unique solidification behaviour due to their chemical long-range order. This includes, for instance, generally slow solidification kinetics, and in some cases, an anomalous partitioning behaviour. In the present work the electromagnetic levitation technique – complemented by theoretical modelling – is used to explore various aspects of this behaviour, as observed in solidification of B2 phase in undercooled melts of the Ni-Al system. Moreover, a phase-field model is developed and used to illustrate the effect of chemical order on the solidification kinetics of a B2 phase in a model system. The phase-field model provides an additional basis for the simulation of solidification microstructures in intermetallic forming systems. Both experimental studies and theoretical work signify the role of chemical order in solidification of intermetallics.