Size and composition effects on the melting of bimetallic Cu-Ni clusters studied via molecular dynamics simulation

The melting points of bulk Cu-Ni over the complete range of compositions were simulated by a model of molecular dynamics with general embedded atom method (EAM). The melting point of bimetallic Cu-Ni clusters was also studied by using the same model. The results show that the changing trend of the simulated melting points for the bulk Cu-Ni agrees with the experimental phase diagram very well. The melting point of the cluster increases with the increase of Ni composition and the increasing trend agrees well with the theoretical phase diagram of bimetallic nanoparticles. The melting point of the cluster is higher than those of clusters without segregation and composition-dependent because the segregation of Cu atoms decreases the melting point. The simulation for the size-dependent melting points of the clusters with 20%, 50%, and 80% Ni shows a linear relation between the inverse cluster sizes and the melting points. The linear relation is not affected by the segregation