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M: Metallphysik

M 35: Amorphe Metalle / Metastabile Materialien II

M 35.1: Fachvortrag

Freitag, 30. März 2001, 12:15–12:30, S8

Atomic dynamics of rapidly quenched and slow cooled NiPdP-glass — •J.- B. Suck¹ and O. A. Petrenko² — ¹TU-Chemnitz, Institute of Physics, Materials Research and Liquids, 09107 Chemnitz, Germany — ²ISIS-Facility, RAL, Chilton, Didcot, Ox11 0QX, UK

NiPdP belongs to those few alloys from which one can produce bulk

glasses by slow cooling from the melt. By melt-spinning techniques it

can be produced as glass as well, however with a quench rate which

exceeds the slow cooling by about 4 orders of magnitude. In this

process strong density fluctuations("defects") are quenched into the

glass.

We have used neutron inelastic scattering at the thermal neutron

time-of-flight spectrometer MARI at the spallation source ISIS, UK to

investigate the influence of these density fluctuations on the atomic

dynamics of metallic glasses. The "defects" in the glass lead, in the

low energy dynamics, to the same kind of changes as obseverd

previously for fcc-Al: an enhancement of the vibrational density of

states, an excess specific heat and a lowering of the Debye

temperature.