Dresden 2011 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 16: Structural Materials

MM 16.2: Vortrag

Dienstag, 15. März 2011, 11:15–11:30, IFW D

Short-range order in Ni-rich Ni-W alloys investigated by synchrotron measurements and first-principles calculations — •Nils Schindzielorz¹, Sascha Maisel¹, Alexey Bosak², Harald Reichert², and Stefan Müller¹ — ¹Technische Universität Hamburg-Harburg, Institut für Keramische Hochleistungswerkstoffe, Denickestr. 15, D-21073 Hamburg — ²European Synchrotron Radiation Source (ESRF), 6 Rue Jules Horowitz, F-38043 Grenoble

Ni-rich Ni-W alloys show a whole zoo of short-range order phenomena as observed by diffuse X-ray scattering. It will be shown that the quantitative analysis of these patterns can be successfully performed by the combination of X-ray scattering and ab-initio based calculations. For the latter, the combination of density functional theory with the cluster expansion method as realized in the computer code UNCLE and Monte-Carlo simulations is applied. This allows us to predict the short-range order in real and k-space as a function of concentration and temperature. The predicted patters are compared with experimental data. It turns out that the short-range order in Ni-W can only be explained by the simultaneous existence of different structure types, where the D16 compound plays one important role.