Dresden 2009 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

MM: Fachverband Metall- und Materialphysik

MM 42: Nanostructured Materials III

MM 42.3: Vortrag

Donnerstag, 26. März 2009, 14:30–14:45, IFW A

Size-dependence melting transformation of nanoparticles confined in an Al-rich glass — •Nancy Boucharat¹, Harald Rösner², and Gerhard Wilde² — ¹Forschungszentrum Karlsruhe, Institut für Nanotechnologie, Karlsruhe — ²Universität Münster, Institut für Materialphysik, Münster

A common way to study the size dependence of the melting transformation is given by incorporating nanoparticles within a matrix. This configuration implies additional contributions related to the nature of the interfaces between the particles and the host matrix which strongly affect the melting process. Thus, the incorporation of nanoparticles within a glassy matrix opens a new angle to revise the size-dependence of melting by limiting the constraints imposed on the particles by the presence of a crystalline matrix with anisotropic lattice mismatch. Here, AlYFe glasses containing immiscible Pb or In additions have been synthesized via rapid solidification. As expected for liquid-liquid phase separation, the Pb-containing samples consist of spherical Pb inclusions homogeneously dispersed within the matrix. In contrast, the In-containing samples show non-crystalline In-enriched regions. Applying a subsequent low-temperature treatment involves the crystallization of spherical particles with sizes smaller than 5 nm, which melt at extremely low temperatures compared to the bulk material. In this context, the melting behavior is discussed with respect to the size dependence and to the energetic contributions from the particle/matrix interfaces.