In situ high-resolution electron microscope observation of phase change in nanometer-sized alloy particles

From the study of alloy phase formation in nanometer-sized particles by in situ transmission electron microscopy, it is revealed that not only the surface energy but also the interface energy of an interface between two different phases (solid-solid or solid-liquid) significantly changes the phase equilibrium of nanometer-sized particles. These energies result in large suppression of the eutectic point, structural instability, and unique solid/liquid two-phase structures in isolated nanometer-sized alloy particles. A theoretical study based on thermodynamics, which is modified in such a manner that Gibbs free energies for bulk materials were modified by taking factors affecting the phase equilibrium of nanometer-sized alloy particles into consideration, was proved useful to evaluate the results obtained from experiments.