Phase-field microelastic modeling of microstructure evolutions in free-standing thin films

Phase-field microelastic modeling of microstructure evolutions in free-standing thin films is developed. Khachaturyan’s microelasticity theory is reformulated to account for the plane-stress condition of free-standing thin films. As examples, the model is applied to simulate two-phase (disordered face-centered cubic + ordered L12) microstructures formed by decomposition and ordering in free-standing thin films of different orientations. Significant effects of the film orientation on the precipitate microstructure morphology are observed, which are analyzed in terms of the anisotropy of the orientation-dependent effective elastic modulus tensor of the free-standing thin films. Distinctive microstructure features in free-standing thin films are discussed in comparison with that observed in bulk materials.