Regensburg 2004 – wissenschaftliches Programm

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M: Metallphysik

M 24: Nanoskalige Materialien III

M 24.1: Vortrag

Donnerstag, 11. März 2004, 10:15–10:30, H16

Melting behavior of Pb and In nanoparticles dispersed in AlYFe matrix — •Nancy Boucharat, Harald Roesner, and Gerhard Wilde — Forschungszentrum Karlsruhe, Institute of Nanotechnology, Postfach 3640, 76021 Karlsruhe

Nanocomposites consisting of nanoscale Pb or In particles dispersed within a crystalline Al matrix have attracted particular attention since considerable deviations in the Pb and In melting temperatures have been observed compared to that of the bulk. Beyond the nano-size effect, several proposals involving contributions of the crystalline matrix (e.g. grain boundaries, strains and defects, lattice orientation relationship) have been advanced to account for the modified melting behavior. Thus, the incorporation of Pb and In nanoparticles in marginal glass formers gives a new opportunity to wider the understanding of the impact of the matrix on the melting behavior, especially to study the size-dependent melting behavior without the constraints imposed on the particles by a crystalline matrix. Therefore, the melting behavior of Pb and In nanoparticles embedded in rapidly quenched AlYFe glass have been investigated by calorimetry and structural analyses. The results indicate a general decrease of both melting temperatures. Moreover, the shift of melting temperatures was found to be strongly correlated to the matrix microstructure, i.e. whether the matrix is in an amorphous state, contains Al-nanocrystal dispersions or is in a fully crystallised state.