Berlin 2008 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 37: Intermetallic Phases II
MM 37.3: Talk
Thursday, February 28, 2008, 10:45–11:00, H 0111
Determination of order parameters and site occupation by means of Atom Probe Tomography — •Torben Boll1, Talaat Alkassab1, Zhi-Guo Liu2, and Lei Shi1,2 — 1Institut für Materialphysik der Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen — 2Laboratory of Solid State Microstructures, Nanjing University, Hankou Road 22, Nanjing 210093, China
An algorithm, that uses statistical methods for the determination of site occupation and order parameters, was developed and applied on various samples.
These samples, consisting of dual phase α2/γ-TiAl-specimen (L10-structure) with Additions of either 3at.%Cr, 2at.% Ag or 1-10at.% Nb were produced by means of leviation melting, respectivly. For comparison within this study a standard intermetallic phase of CuAu was fabricated as well.
The Atom Probe Tomography (APT)-results are presented and compared with X-Ray-Diffraction (XRD) and Atomic Location by Channeling-Enhanced Microanalysis (ALCHEMI).
Field ion Microscopy (FIM) images allow general statements about site occupation, if assumptions about the imaging behavior of the involved elements are made. Concerning the order it is only possible to state, whether the sample is well ordered or not.
In contrast, with the developed APT-algorithm it is furthermore possible to attain information about the field evaporation field strengths of the different components in the respective unit cells.