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M: Metallphysik

M 17: Phasenumwandlung II

M 17.3: Vortrag

Samstag, 5. März 2005, 11:30–11:45, TU H1058

Determination of Atomic Interaction Parameters from X-Ray Diffuse Scattering in the Binary Alloy System Ni-Pd — •Markus Mezger^1,2, Harald Reichert¹, and Helmut Dosch^1,2 — ¹Max-Planck-Institut für Metallforschung, Heisenbergstr. 3, D-70569 Stuttgart — ²Universität Stuttgart, Institut für Theoretische und Angewandte Physik, Pfaffenwaldring 57, D-70550 Stuttgart

Macroscopic properties of alloys, such as the elastic constants, are determined by the atomic interaction potential between the different alloy components. These parameters are encoded in the diffuse scattering caused by configurational short range order (SRO) and lattice distortions in the disordered phase. For the Ni-Pd alloy system we present a method to obtain the interaction parameters directly from X-ray diffuse scattering. In order to collect the experimental data in-situ meassurements on macroscopic Ni₅₅Pd₄₅ and Ni₂₅Pd₇₅ single crystals were performed in the temperature range from 20 ^∘C up to 900 ^∘C. For the data analysis a formalism based on the spherical model and the Kanzaki-force concept has been used within a simulated annealing algorithm.