Dresden 2006 – scientific programme

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MM: Metall- und Materialphysik

MM 38: Nanostructured Materials II

MM 38.5: Talk

Thursday, March 30, 2006, 17:30–17:45, IFW D

The influence of interfaces on the properties of nanostructured materials considering the different melting behaviour of Al-Pb composites — •Harald Rösner, Jörg Weissmüller, and Gerhard Wilde — Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft, Institut für Nanotechnologie

Al-Pb composites composed of nanometre-sized Pb particles embedded in a polycrystalline Al matrix serve as a model system for size-dependent melting studies. Depending on the processing pathway, i.e. ball-milling or melt-spinning, the Pb nanoparticles either display a faceted morphology or are spheroidical with curved interfaces. The faceted and spheroidical particles were observed to melt at temperatures above and below the melting temperature of bulk Pb, respectively. However, the observed difference in melting behaviour cannot be explained purely by the different morphologies exhibited by the particles. Recent high-resolution TEM investigations showed that two types of misfit dislocations are present at the interfaces in both types of particles. Based on these results we present a new model that accounts for the different melting behaviour by considering the different mobility of atoms at curved and faceted Al-Pb interfaces.