Unveiling load carriers between nanoparticles capable of passing through a glassy disordered phase: A theoretical multiscale analysis

In the design and manufacturing of ultra-fine grained materials, it is important to understand the competitive relationship between grain growth and intergranular bonding under thermal loads. The key is to understand the mechanisms by which the load transfer is initiated between the surfaces of the glassy disordered phase, at the atomic level. In this regard, the initiation of load transfer through the glassy disordered phase during the binding of Y ₂O ₃ nanoparticles was investigated in silico. Multiscale analysis combining quantum mechanics and classical molecular dynamics simulations showed that the disordered phase structure between Y ₂O ₃ nanoparticles exhibits high resistance to shear deformation. However, yttrium cations and oxygen anions exhibit opposing mechanical roles within the disordered phase. The steric deformation exhibited by anion-biased electronic structures with perpendicular O 2 p and Y 4 d – O 2 p overlap allows the yttrium cation to contribute to the phase transition, while the oxygen anion directly participates in load transfer. The analysis of phase transition kinetics, including the experience of transition states, provides the composition and distribution of the energy levels of the disordered phase, thereby explaining the origin of the differences in the roles of atomic species.