Simulation of Intermetallic Solidification Using Phase-Field Techniques

We have presented current ideas towards developing a phase-field model appropriate to the solidification of intermetallic phases. Such simulation presents two main challenges (1) dealing with faceted interfaces and (2) the complex sublattice models used to describe the thermodynamics of such phases. Although models already exist for the simulation of faceted crystals, some of these can be shown to produce highly unrealistic Wulff shapes. The model present here uses a parameterisation 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 sublattice) thermodynamics is presented. Such anti-trapping currents are vital in the simulation of intermetallic phases where the steep liquidus slope means small deviations in solute partitioning behaviour leading to a significant change in tip undercooling.