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MM: Fachverband Metall- und Materialphysik
MM 38: Liquid and Amorphous Metals
MM 38.6: Vortrag
Mittwoch, 28. März 2012, 16:15–16:30, H 1029
A study of phase separation in Zr-Gd-Co-Al metallic glasses — •Junhee Han1,2, Norbert Mattern1, and Jürgen Eckert1,2 — 1IFW-Dresden, Institute for Complex Materials, Dresden, Germany — 2TU Dresden, Institute of Materials Science, Dresden, Germany
The Zr-Co-Al and Gd-Co-Al ternary alloys are well known bulk metallic glass-former that could be cast into cylindrical rods with diameters up to 18 mm and 5 mm, respectively [1-2]. Since the binary Zr-Gd system has a miscibility gap in the solid state, i.e. Zr and Gd tend to separate from each other, the quaternary Zr-Gd-Co-Al system is a promising candidate to form phase separated glass-glass composites. In this work, Zr56-xGdxCo28Al16 ( x = 2 - 20 at.%) melt-spun ribbons are characterized. The structure are further studied by In-situ small-angle and wide-angle X-ray scattering (SAXS/WAXS) at elevated temperature. Heat treated ribbons for x = 5 and 10 are additionally investigated by atom probe tomography. For ribbons with relatively low Gd content (x = 10 at. %), no indication for phase separation is found by general analysis such as SEM, XRD and DSC. In-situ SAXS/WAXS at elevated temperature gives evidence for formation of heterogeneity prior to crystallization. Atom probe tomography measurement also illustrates that the ribbons x = 5 and 10 undergo phase separation resulting in Gd-rich nano-scale precipitates prior to crystallization.
This study is supported by the Deutsche Forschungsgemeinschaft (Ma1531/10).
[1] T. Wada et al., J. Mater. Res, 24(2009)8
[2] D. Chen et al., Mater. Sci. Eng. A, 457(2007)226