Structural and Thermodynamic Behaviors of Cu_mAg_n (m + n = 144–147) Nanoalloys during Cooling: Implications for Nanoparticle Structure Control

Molecular dynamics simulations are performed to explore the structural and thermodynamic changes of four nanoalloys with the addition or removal of one atom during cooling. The simulation results reveal that there are significant differences in the structural diagrams of the nanoalloys from potential energy, free energy, and entropy as well as visually atomic packing images and pair distribution functions. There are apparent effects of compositions and sizes on the structural transitions as well as the transition process. The results also show that during the cooling processes, there are multi-structural transition processes for the nanoalloys having different compositions, and most of the nanoalloys show a transition from a liquid state to a core–shell metastable packing structure and then to an Ih packing structure. The compositions and atom numbers as well as the shape also affect the thermodynamic quantities. The findings contribute to the understanding of fundamental issues involved in alloying between Cu and Ag metals and are important for the precise control of the preparation of Cu–Ag nanoalloys with specific structures.