Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 52: Phase Transformations I

MM 52.2: Vortrag

Donnerstag, 14. März 2013, 10:30–10:45, H26

Analysis of the melting point depression and the structure of Bi nanoparticles embedded in Zn matrix — •Tae-Eun Song, Martin Peterlechner, and Gerhard Wilde — Institute für Materialphysik, Wilhelm-klemm-straße 10, D-48149 Münster, Germany

The melting point depression of embedded Bi nanoparticles in a Zn matrix synthesized by rapid solidification was analyzed using Differential Scanning Calorimetry (DSC) and Transmission Electron Microscopy (TEM). TEM shows an elongated and faceted morphology of Bi nanoparticles. The elongated Bi particle (012) facet is arranged parallel to Zn (002). Upon heating in the DSC two Bi melting signals occur, one close to the bulk melting temperature and the other at a lower temperature. Subsequent cooling leads to two solidification signals. During repeated heating and cooling, some Bi particles are solidified at a small undercooling with a number of exothermic peaks, whereas other Bi particles are solidified with a broad exothermic peak at a larger undercooling. Thermal cycling below the bulk Bi melting temperature leads to a gradual decrease of the solidification enthalpy at larger undercoolings. The results are discussed in the framework of size confinement and interface control of phase transformations.