Precipitation Hardening has become an alternative to doping with foreign atoms in ferroelectric material. It effectively reduces heat dissipation due to hindering of domain wall motion. Thus, the mechanical quality factor of ferroelectric material can be enhanced by introducing precipitates on the micro-scale of the material. However, the optimal shape and size of the precipitates and their influence on the spontaneous polarization of the material remains an open question. This work aims at modelling the polarization of heterogeneous ferroelectric material with a phase field approach. The domain formation and pinning of domain walls is simulated with finite element computations with the goal to determine favorable shapes of precipitates.