Melting thermodynamics of nanocrystals embedded in a matrix

A simple model, free of any adjustable parameter, is established for the me lting temperature and melting entropy of nanocrystals embedded in a matrix where the interface between the nanocrystals and the matrix is coherent. Th e model is based on Lindemann's criterion for the melting, Mott's equation for the melting entropy of bulk crystals and our model for the size-depende nt melting temperature. It is shown that the melting temperature and the me lting entropy of nanocrystals embedded in a matrix increase as the size of the nanocrystals decreases. The above predictions are supported by availabl e experimental results on Pb and In nanocrystals embedded in an Al matrix. On the basis of the model, the melting mechanism of superheating is discuss ed. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.