Melting temperature of In particles embedded in an Al matrix

Abstract

The melting and freezing temperatures of small In particles with a radius r of less than 20 nm embedded in an Al matrix have been measured as a function of particle size using in situ heating in an electron microscope. The melting temperature of In particles whose radii are smaller than 15 nm is higher than that of bulk material and increases with decreasing r. The freezing temperature is lower than the melting temperature of bulk material for all radii studied and has a minimum at around r = 13 nm. The behaviour of the melting of embedded particles contrasts sharply with that of free particles, for which the melting temperature decreases with decreasing r. The difference is discussed in terms of the interfacial energies between the Al matrix and liquid or solid In.