Determination of melting mechanism of Pd 24Pt 14 nanoalloy by multiple histogram method via molecular dynamics simulations

Abstract

Melting mechanism for the Pd 24Pt 14 nanoalloy has been determined by classical simulations in which quenching by the steepest descent method is coupled to the isothermal molecular dynamics and the nonergodicity of simulations is removed by the multiple histogram method. The Gupta many-body model is used for interatomic potentials. The melting characteristics are determined by the analysis of variations in the potential energy, the heat capacity, the vibrational density of states and the self time–space correlation functions with temperatures starting from 50 K up to 2200 K. The calculations indicate that the melting of Pd 24Pt 14 nanoalloy occurs at T = 747 K following structural transitions from the truncated-octahedral to the icosahedral basin of structures. A postmelting phenomenon has also been observed at temperatures between 900 and 1100 K, which is related to the homogeneous melting. This improves our knowledge about the phase transition features in 38-atom nanoalloys.