Regensburg 2004 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
M: Metallphysik
M 9: Flüssige und amorphe Metalle III
M 9.2: Vortrag
Montag, 8. März 2004, 16:45–17:00, H16
Microstructure, thermal stability and mechanical properties of slowly cooled Zr-based composites containing dendritic bcc phase precipitates — •Nicolle Radtke1, Juergen Eckert2, Uta Kuehn1, Mihai Stoica1, and Ludwig Schultz1 — 1IFW Dresden, Institut fuer Metallische Werkstoffe, Postfach 270016, 01171 Dresden, Germany — 2TU Darmstadt, Institut fuer Physikalische Metallkunde, Petersenstr. 23, 64287 Darmstadt, Germany
We report on the microstructure, the thermal stability and the mechanical properties of slowly cooled Zr-Nb-Cu-Ni-Al alloys with ductile bcc phase precipitates embedded in a glassy or nanocrystalline matrix. The samples were prepared in form of rods by injection casting into a copper mold. The phase formation and the microstructure of the composite material were investigated by X-ray diffraction, EDX analysis and scanning and transmission electron microscopy. The thermal stability was examined by differential scanning calorimetry and the mechanical behavior was investigated by compression tests under quasistatic loading at room temperature. The formation of bcc phase dendrites and a glassy or nanocrystalline matrix is strongly governed by the alloy composition and the actual cooling rate during solidification. Besides, changes in composition and cooling rate lead to different volume fraction and size of the bcc phase precipitates and, hence, to different values of yield strength, elastic and plastic strain. Illustrated by the presented results we show the possibility of obtaining tailored mechanical properties by control of composition and solidification conditions.