Regensburg 2007 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 20: Poster session

MM 20.20: Poster

Dienstag, 27. März 2007, 14:45–18:00, Poster C

Primary crystallization of the hypoeutectic Ni-17at% P alloy by ASAXS and SANS — Dragomir Tatchev¹, •Rainer Kranold², Armin Hoell³, Günter Goerigk⁴, and Stephan Armyanov¹ — ¹Institute of Physical Chemistry, BAS, Sofia 1113 — ²Institute of Physics, Rostock University, Rostock — ³Hahn Meitner Institute, Glienicker Str. 100, Berlin — ⁴Institute of Solid State Research, Jülich Research Centre, P.O. Box 1913, Jülich

We investigated the primary crystallization of Ni(P) particles in the amorphous hypoeutectic Ni-17 at.% P alloy with anomalous small-angle X-ray scattering (ASAXS) [1] and small-angle scattering of polarized neutrons (SANS) [2]. Using the maximum entropy method, the particle size distribution, the size dependence of the particle composition and the amorphous matrix composition were determined simultaneously. The size distribution shows a peak at particle radius of 1 nm and a tail spanning from 2 to 15 nm. The composition of the particles of the peak changes from 14 to 2 at.% P as their radius grows from 0.7 to about 3 nm. The particles in the tail of the size distribution (2-15 nm) have nearly constant P content in the range of 0-2 at.%. The matrix composition tends to the eutectic composition with 19 at.% P at the end of the primary crystallization process. It should be mentioned that our experimental results completely confirm the predictions made in a generalized Gibbs’ approach to nucleation theory [3] developed recently. [1]D. Tatchev et al., J. Appl. Cryst. 38 (2005) 787. [2]D. Tatchev et al., Physica B 369 (2005) 8. [3]J.W.P. Schmelzer et al., J. Colloid Interface Sci. 272 (2004) 109.