Simulation of a Nonequilibrium Melting Process of Copper Nanoparticles Using a Molecular Dynamics Method

To study the behavior of a nanosystem under the influence of a volumetric heat source with power density of 0.012 and 0.0035 eV/(atom ns) analytical and numerical simulation of the melting of three-dimensional copper particles containing 8 and 32 million atoms was performed. The results obtained show that for a nanoparticle having free boundaries the critical power density of the source which initiates the nonequilibrium melting regime depends on the particle size. Below the critical power value, the melting mode has only superficial character. Upon reaching a critical power, along with the initial melting of the surface there is a strong overheating and subsequent melting of the central part of the particle. In this case, the phase transition of the nanoparticle proceeds in a nonequilibrium mode additionally acquiring a volume character.