Regensburg 2002 – wissenschaftliches Programm

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M: Metallphysik

M 12: Amorphe und metastabile Metalle III

M 12.6: Fachvortrag

Dienstag, 12. März 2002, 15:45–16:00, H4

ZrNbCuNiAl bulk metallic glass matrix composites containing dendritic bcc phase precipitates — •Uta Kühn, Jürgen Eckert, Norbert Mattern, and Ludwig Schultz — IFW Dresden, Postfach 270016, 01171 Dresden

We report on multicomponent ZrNbCuNiAl alloys with a glassy or a nanocrystalline matrix and ductile bcc precipitates. The samples were prepared in form of rods by injection casting into a copper mold. The structure of the as-cast samples was characterized by X-ray diffraction and transmission electron microscopy. The thermal stability was examined by differential scanning calorimetry.

The formation of the bcc phase embedded in a glassy matrix is strongly governed by the alloy composition and the actual cooling rate during solidification. Already small changes in composition lead to precipitation of a second unknown crystalline phase or of quasicrystals. This indicates that the tendency of formation of the glass, the quasicrystalline and the bcc phase are closely correlated. Room temperature compression tests reveal that the in-situ glass-matrix composite undergoes work hardening and plastic deformation prior to failure. This significantly improves the mechanical behaviour of the composite compared to the monolithic glass and extends the range of possible applications.