Simulation of the Si Precipitation Process in Mg2Si Using a Phase-Field Kinetic Model

The Si precipitation process in an Mg2Si matrix has been simulated by the phase-field kinetic model, considering the eigen strain at the interface between precipitates and the matrix. We observed that the shape of the precipitate changed during the course of heat treatment from circular to lenticular. As the Si precipitate grew larger, the adjacent precipitate aggregated to form a lamellar microstructure. This microstructure is suitable for thermo-electric materials because the scattering of phonons will frequently occur at the interface between the Si precipitates and the Mg2Si matrix. Our present simulation suggests drastic improvements of thermo-electric properties of this type of material are possible due to the eigen strain.