The dynamics of precipitate evolution in elastically stressed solids - II. particle alignment

The effects of elastic stress on the spatial distribution and morphology of misfitting particles during coarsening in an elastically anisotropic system are examined. No assumptions are made on the morphology of the particles; they evolve in a manner consistent with the diffusion and elastic fields in the system. Through these calculations we have identified the microstructural signature of elastic-stress induced particle migration. In addition, we find that elastic stress leads not only to particle alignment along the elastically soft directions of the crystal, but also prevents particle coalescence. When the particles are aligned along the elastically soft directions of the crystal the morphology of the particles differs from the equilibrium shape of isolated particles in a manner which depends on the size of the particles. In addition, the elastic-stress induced equilibrium separation between aligned particles decreases with increasing particle size. We show that the effects of elastic stress, due to either applied tractions or other particles, on the morphology and spatial distribution of the particles can be understood in terms of the configurational forces generated by this stress. Configurational force fields generated by misfitting particles are used to explain the results of our dynamical calculations.