Dresden 2003 – wissenschaftliches Programm
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M: Metallphysik
M 38: Flüssige und amorphe Metalle III
M 38.2: Vortrag
Donnerstag, 27. März 2003, 10:30–10:45, IFW D
CRYSTALLIZATION BEHAVIOR OF Pd40Cu30Ni10P20 BULK GLASS — •Eugen Davidov, Nelia Wanderka, Michael-Peter Macht, and Volkmar Naundorf — Hahn-Meitner-Institut Berlin, Glienicker Str. 100, 14109 Berlin, Germany
The Pd40Cu30Ni10P20 glass is one of the most stable metallic bulk glasses. The decomposition and crystallization behavior of this glass in the as-cast state and in the supercooled liquid state was investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM) and by the three-dimensional atom probe (3DAP). In the as-cast state, the analysis did not show any indication of crystals. Statistical analysis of the 3DAP-results revealed that the as-cast glass was chemically homogeneous. The crystallization behavior of the glass was investigated by annealing at different temperatures above the glass transition for different times. Multistage interdependent crystallization of at least five different phases was observed. E.g. at 590 K, large dendrites, rich of Ni and poor of Cu and Pd appear at first after about 20 h. The surrounding amorphous matrix is accordingly decomposed. After longer annealing such crystals grow to rather large (size > 100 µm) multiphase crystalline regions with the same integral composition as the glass. However, the microstructure which develops during crystallization at petty higher temperatures (e.g. at 600 K) is partly composed of different phases.