The phase transition between liquid and solid phases of the substrate-supported nanoparticles of iron, chromium, molybdenum and tungsten with size ranging from 2000 to 31 250 atoms was investigated by molecular dynamics simulation. Unidirectional solidification and inward melting after surface melting occurred during cooling and heating, respectively. It was found that the depression of the melting point due to size effect correlates with the shape of the nanoparticle (i.e. contact angle), whereas that for solidification point correlates with the interaction energy between the nanoparticle and substrate. (C) 2009 Elsevier B. V. All rights reserved.