Structural Diagrams and Thermodynamic Behaviors of CunAg143-n (n = 0 ∼ 143) Alloying Nanoparticles During Cooling: Implications from Atomic Simulations.

Structural diagrams and thermodynamic function quantities of CunAg143-n (n = 0 ∼ 143) alloying nanoparticles are studied by molecular dynamics simulations within the framework of embedded atom method potential. The simulation results at atomic scale show that the alloy composition has a significant effect on the changes of the free energies and shapes of molten nanoparticles. The structural diagrams reveal structural transition characteristics of the binary nanoparticles at different temperatures on cooling, where the transition temperature between the liquid, α, γ, Ih, and β structures changes significantly with changing Cu atomic number in the particles. The binary nanoparticles show significantly different packing patterns from their bulk counterparts. Typical alloying particles with different compositions exhibit diversities in packing patterns. These findings contribute to the understanding of the fundamental issues involved in alloying among Cu and Ag atoms, which are important for precisely controlling the preparation of Cu-Ag nanoalloys with specific structures.