Simulation of Intermetallic Solidification using Phase-Field Techniques

We present current ideas towards developing a phase-field model appropriate to the solidification of intermetallic phases. Such simulation presents two main challenges (i) dealing with faceted interfaces and (ii) the complex sub-lattice models used to describe the thermodynamics of such phases. Although models are already existent for the simulation of faceted crystals, some of these can be shown to produce highly unrealistic Wulff shapes. The model present here uses a parameterization of the Wulff shape as a direct input to the model, allowing the simulation of arbitrary crystal shapes. In addition, an anti-trapping current that can be used with arbitrary (including sub-lattice) thermodynamics is presented. Such antitrapping currents are vital in the simulation of intermetallic phases where the steep liquidus slope means small deviations in solute partitioning behaviour can translate to a significant change in tip undercooling.