Superheating and melting kinetics of confined thin films

Pb thin films confined in Al were synthesized by means of repeated cold-rolling from stacked Al/Pb/Al sandwiches and magnetron sputtering deposition, respectively. The layer thickness of the confined Pb thin films was in a range of 6-27 nm. Differential scanning calorimetry (DSC) was used to systematically study the melting behavior of the confined Pb thin films. Above the equilibrium bulk melting point, a melting peak of superheated Pb was noticed in DSC traces. The degree of superheating increases with a decreasing film thickness and an increasing heating rate. The melting kinetics of the superheated Pb thin films is analyzed in terms of the lateral growth mechanism. The observed superheating of Pb thin films is attributed to the suppressed melt growth by the epitaxial Pb/Al interfacial configuration. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.