An Al-4.5% Cd alloy has been manufactured by melt spinning to produce a microstructure of 14-150 nm diameter faceted cadmium particles embedded in an aluminium matrix. The melting behaviour of the cadmium particles has been investigated by differential scanning calorimetry. The melting point of 20 and 14 nm diameter cadmium particles embedded are depressed by 7 and 9 K respectively, below the bulk equilibrium cadmium melting point, because of Gibbs-Thomson capillarity effects. The average solid cadmium particle/aluminium matrix interfacial energy is 27 mJ m-2 higher than the average liquid cadmium particle/aluminium matrix interfacial energy. No significant superheating is needed to nucleate cadmium particle melting.