Dresden 2003 – scientific programme

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M: Metallphysik

M 41: Postersitzung

M 41.33: Poster

Thursday, March 27, 2003, 14:30–16:30, HSZ

Glass-forming ability and crystallization behaviour of Zr-Ti-Cu-Ni-Al bulk amorphous alloys with different Ti contents — •Uta Kuehn, Norbert Mattern, Tanja Shapoval, and Juergen Eckert — IFW Dresden, P.O. Box 270016, D-01171 Dresden

Bulk amorphous Zr_62−xTi_xCu₂₀Ni₈Al₁₀ alloys were prepared in the composition range of x = 0 to 7.5 by copper mould casting with a thickness of 3 mm in diameter. The thermal stability and the crystallization behaviour of the as-cast states were characterized by DSC measurements and the structure was studied by XRD and TEM. The mass density of the as-cast samples and of the different annealed states was determined. The difference in density changes between as-cast glassy, relaxed and crystallized structures depending on the Ti content of the alloys. The higher the packing fraction of the glassy state is, the higher is the thermal stability of the bulk glass due to a decrease in atomic mobility. The crystallization behaviour of the different compositions, concerning the size and the structure of the crystals formed, also depends strongly on the Ti concentration. Some compositions of this alloy system form a metastable quasicrystalline phase during the first step of crystallization. Furthermore, the annealing conditions as well as the heating rate may influence strongly the crystallization process.