Molecular dynamics simulation of a core-shell structured metallic nanoparticle

This study investigates the heating and cooling of a shell-core structured Ni-Al functional particle through a molecular dynamics simulation. The functional nanoparitcle is constructed from their perfect crystal measuring 5.6 nm in diameter with a shell thickness of 0.5 nm. The simulation is carried out within a Nosé-Hoover thermostat scheme of the NVT canonical ensemble and performed by an Embedded-Atom-Method (EAM) force field. The thermodynamic properties and structure evolution during continuous heating and cooling processes are investigated through the characterization of the gyration radius, radial distribution function (RDF), atom number distribution, mean-square-distance (MSD), and layered potential energy distribution. Some unique behaviors related to nanometer scale functional particles are identified that include two-way diffusion of aluminum and nickel atoms, enhanced melting of the aluminum core through the shell structure, glass phase formation for the fast cooling rate, and the Ll₂ Ni₃Al phase formation under a low cooling rate.