Dresden 2011 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 12: Postersitzung I

MM 12.3: Poster

Montag, 14. März 2011, 17:30–19:00, P5

Combined in-situ SAXS/WAXS and HRTEM Study on Crystallization of (Cu₆₀Co₄₀)_1−xZr_x Metallic Glasses — •B. Schwarz¹, U. Vainio², N. Mattern¹, S.W. Sohn³, D. H. Kim³, and J. Eckert¹ — ¹Leibniz-Institute IFW Dresden, Institute for Complex Materials — ²HASYLAB at DESY, Hamburg — ³Department of Metallurgical Engineering, Center for Noncrystalline Materials, Yonsei University, Seoul, South Korea

The binary Cu-Co system exhibits a metastable liquid-liquid miscibility gap and therefore the ternary Cu-Co-Zr system is a promising candidate to form phase separated glass-glass composites. In this work (Cu₆₀Co₄₀)_1−xZr_x metallic glasses with x=37 and x=32 were investigated by in-situ small-angle and wide-angle x-ray scattering (SAXS/WAXS) and differential scanning calorimetry (DSC). Certain heat treated samples were additionally investigated by high-resolution transmission electron microscopy (HRTEM). Even for x=32 there are no indications for any kind of phase separation in the as-quenched state within experimental resolution, i.e. the critical temperature T_c for liquid-liquid phase separation has already decreased from 1556 K for binary Cu₆₀Co₄₀ to a temperature below the glass transition temperature T_g = 762(5)K found for (Cu₆₀Co₄₀)₆₈Zr₃₂. Combined in-situ SAXS/WAXS and HRTEM investigations reveal that thermal annealing induces the formation of a composite consisting of nano crystallites embedded in an amorphous matrix.

nano