Regensburg 2010 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 34: Liquid and Amorphous Metals I
MM 34.4: Talk
Wednesday, March 24, 2010, 11:00–11:15, H5
Heterogeneous Gd-Hf-Co-Al metallic glasses by liquid-liquid phase separation — Jun Hee 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 unique microstructures of phase separated metallic glasses can lead to enhanced properties of materials with its heterogeneity. Phase separated metallic glasses were prepared in Gd-Hf-Co-Al system by rapid quenching of the melt. The compositions were chosen by the combination of Gd-Co-Al and Hf-Co-Al alloys showing high glass forming ability. Strong positive enthalpy of mixing (ΔHmix)between the principal elements Gd and Hf leads to a heterogeneous microstructure of Gd-Hf-Co-Al glassy alloys consisting of two amorphous phases Gd-enriched and Hf-enriched. The length scale of spherical shaped heterogeneities ranges from a few nanometers to tens of micrometers. For clearly phase separated composition with nano-meter scale (~100nm) secondary phase separation is observed in each amorphous phase. Furthermore, thermal behaviour of Gd-Hf-Co-Al phase separated metallic glasses was investigated in order to analyze the composition dependence of glass transition temperature (Tg) and crystallization temperature (Tx), as well as phase sequences upon heating. Funded by DFG Ma1531/10.