Berlin 2005 – scientific programme

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M: Metallphysik

M 32: Poster TU B (Symposium Tomographic Methods in Materials Research M-32.32-55)

M 32.52: Poster

Monday, March 7, 2005, 14:30–16:30, Poster TU B

Investigation of rheological behaviour of binary alloys with synchrotron radiation — •Rueda A.¹, Zabler S.¹, Rack A.², Haibel A.², and Banhart J.^1,2 — ¹Technische Universität Berlin, Institut für Werkstoffwissenschaften und -technologien, Fakultät III - Fachgebiet Struktur und Eigenschaften von Materialien — ²Hahn-Meitner-Institut Berlin, SF3, Abteilung Werkstoffe

Thixotropic alloys are characterized by a non-dendritic, i. e. globular, solid phase embedded in a melting liquid matrix. Due to the good casting property of the thixotropic alloys they play an important role for engineering applications. One production route of such alloys is the new rheocasting process. At this, the liquid alloy will be casted in a special container and the accruing shear forces cause the building of the globular solid structure. By using this proceeding and with chemical grain refining (AlTiB) we were able to manufacture thixotropic material (AlGe15%) with around 100µm diameter grains. In order to investigate the static and dynamic, i.e. rheological, properties we used synchrotron radiation at BESSY II. By means of high resolution synchrotron radiography we studied the microstructure of our alloy, which is rich in absorption contrast of X-rays. Tomographic images of the thixotropic alloy are used to quantify their globular shape. In radiographic images of micrometer-thin layers we obtained at real time the rheological behaviour, i.e. the grain formation and movement in the mushy state of the alloy.