Most solids are polycrystalline: they consist of multiple crystalline grains separated by grain boundaries. All the grains are equivalent up to a rotation, and the properties of the grain boundaries depend on the relative orientation of the two grains. In particular, the free energy associated with the grain boundary is a function of the misorientation of the grains. During annealing, the total free
energy of the system can decrease through a reduction of grain boundary area (or grain boundary length in two dimensions): some grains grow in size, whereas others are eliminated (coarsening). This evolution becomes self-similar at long times, and the grain size distribution is universal and independent of the initial condition.
This problem has been thoroughly studied in thin metallic films, and numerous 2D numerical simulations have been performed. However, their results remain contradictory. In the framework of a collaboration with the Wigner Research Institute in Budapest, Hungary, we have studied this
problem with a phase field model where crystalline orientation is described by a continuous field. This collaboration was supported by the Hubert Curien program managed by the french Minitry of Forein Affairs for two years
Grain coarsening in two-dimensional phase-field models with an orientation field
Bálint Korbuly, Tamás Pusztai, Hervé Henry, Mathis Plapp, Markus Apel, and László Gránásy
Phys. Rev. E 95, 053303 – Published 9 May 2017
Hervé Henry