Dresden 2006 – wissenschaftliches Programm

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MM: Metall- und Materialphysik

MM 18: Materials Design

MM 18.1: Vortrag

Dienstag, 28. März 2006, 14:45–15:00, IFW B

Three-dimensional analysis of globular microstructures by means of phase sensitive Synchrotron Tomography — •Simon Zabler¹, Andreas Lohmüller², Alexander Rack³, Astrid Haibel¹, Heinrich Riesemeier⁴, Jürgen Goebbels⁴, John Banhart¹, and Antonio Rueda¹ — ¹Hahn-Meitner-Institut Berlin, Abteilung Strukturforschung — ²Neue Materialien Fürth GmbH — ³Forschungszentrum Karlsruhe - ANKA — ⁴Bundesanstalt für Materialforschung und -prüfung Berlin

We investigate materials with globular microstructure as used in Thixocasting processes like A356, A357 and AZ91D alloys. Phase sensitive synchrotron tomography is the ideal non-destructive tool for the analysis of such materials. The effects of growth and coarsening are analysed as well as the dynamics of the semi solid melt.

The aim of our work is to use 3D image processing in order to reveal the correlation between the alloys microstructure and its rheological properties (e.g. viscosity) in the semi solid state. Because all the samples under test represent alloys that are built from neighbouring elements with similar densities (e.g. Aluminium and Silicon) standard absorption tomography lacks any visible contrast in the images. We apply phase contrast imaging yielding a contrast up to three orders of magnitude superior to absorption contrast rendering the microstructure of all the alloys under test visible. Tomography data is available in form of phase sensitive 3D images or holotomographic data sets when the tomographic reconstruction is combined with a direct phase retrieval algorithm.