Hamburg 2001 – scientific programme
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M: Metallphysik
M 20: Symposium Unterkühlte Metallschmelzen VI
M 20.4: Fachvortrag
Tuesday, March 27, 2001, 11:00–11:15, S12
Weakening of Shear Bonds in Supersaturated Solid Solutions — •F. Jurányi1, 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
Reducing diffusion during the production process, e.g. by
low energy ball milling, supersaturated solid solutions can
be formed in a certain concentration region. Supersaturation,
similar to superheating, weakens the bonds in the host matrix.
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 supersaturation
of Al in Zr on the atomic dynamics. The Zr(100-x)Al(x) system
can be driven by supersaturation to an order-disorder
transition, resulting in an amorphous solid. The investigated
samples cover the hole range of interest: stable (x=5) and
supersaturated (x=10) solid solutions and the amorphous (x=20)
one. The results of our experiments show that increasing
supersaturation affects primarily the low energy dynamics:
an enhancement of the vibrational density of states in the
low energy region, an excess specific heat and a lowering of
the Debye temperature. We interprete these results as being
due to an increasing weakening of the restoring forces of
the shear modes on progressing supersaturation.