Effects of elastic interactions on the aggregation of nanostructures

Externally imposed fields can directly affect microstructural evolution arising from diffusional phase separation in binary mixtures and potentially can be utilized to form highly ordered nanostructures. The effects of elastic fields on phase separation and coarsening are investigated in this paper using a Cahn-Hilliard-type phase-field model. Periodic traction distributions are shown to lead to patterned microstructures. The kinetics and morphology of aggregation are found to depend significantly on the transformation strain, contrast in moduli between phases and the magnitude of externally applied tractions (mechanical fields). The trends observed in simulations are analyzed in detail in terms of Eshelby-type estimates for elastic interaction energies, and the correlations are shown to be remarkably accurate. Predictions based solely upon interaction energies can provide very useful guidelines to develop strategies to control the morphology of aggregation.