Regensburg 2010 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 53: Nanostructured Materials IV

MM 53.2: Vortrag

Donnerstag, 25. März 2010, 14:15–14:30, H16

Melting behaviour of embedded Pb nanoparticles in an Al (Ga) matrix — •Anna Moros, Harald Rösner, and Gerhard Wilde — Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster

Melting is one of the most important phase transformation in nature, but its underlying mechanism is still not completely understood. It is well known, that decreasing particle sizes lead to a change of the bulk properties of a material, as for instance a shift of the melting point. Current investigations on the melting behaviour of Pb nanoparticles embedded in an Al matrix are presented. In contrary to the prediction of many models for size-dependent melting, faceted and truncated cuboctahedric Pb nanoparticles with a cube-on-cube orientation relationship to the matrix start to melt 10 - 30 K above the melting point of the bulk material, indicating a more complex dependence of the melting temperature with respect to the particle-matrix interfaces. Here, the melting temperature of the particles was determined by means of differential scanning calorimetry. The size distribution of Pb inclusions in the samples was obtained from TEM images. However, it was observed that the addition of Gallium selectively into the Al matrix led to a significant shift of the melting temperature of the Pb nanoparticles. The experimental results are presented and discussed.