Size dependence and phase transition during melting of fcc-Fe nanoparticles: A molecular dynamics simulation

摘要

Continuous melting and cooling of isolated /cc-Fe nanoparticles with 59-9577 atoms are studied by Molecular Dynamics (MD) simulation with Sutton-Chen potential. An energy minimization process was employed to obtain the stable solid structure for simulation of melting. The energy-minimized nanoparti-cles show lower potential energy and radius compared with the counterparts without energy minimizing The size dependence of melting point shows perfect linear variation with N~(-1/3) for particles above a limit of 113 atoms. The bulk melting temperature of 1833.3 K, which is close to the experimental data (1811K for bcc and 1800.8 K for fcc), has been predicted by a linear relationship. Two different inner structures, including five-fold twinning and lamellar structures, have been found to be the initial stable configura-tions prior to melting, and both surface premelting and internal defects were verified as the origins for melting behavior.