Berlin 2005 – wissenschaftliches Programm

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M: Metallphysik

M 2: Flüssige und amorphe Metalle I

M 2.4: Vortrag

Freitag, 4. März 2005, 11:15–11:30, TU H111

Transformations near the glass transition in Pd-based bulk metallic glasses — •Shantanu V. Madge, Harald Rösner, and Gerhard Wilde — Institute of Nanotechnology, Forschungszentrum Karlsruhe, P.O.B. 3640, D-76021 Germany.

One reason for the current interest in bulk metallic glasses (BMGs) is the complexity that often underlies crystallisation in these alloys, which can involve various metastable phases. Phase separation in the undercooled liquid is an issue that has seen much attention in recent years in order to explain the counter-intuitive nanocrystallisation that occurs in some BMGs. In the present work, a series of Pd-based BMGs has been prepared by suction-casting. The transformations in certain glasses on heating above the glass-transition temperature are investigated in−situ and ex−situ by complementary techniques such as modulated-temperature calorimetry, X-ray diffraction or transmission electron microscopy, including the analysis of the initial crystallization products in the early stages of devitrification. The results are discussed in the light of possible amorphous phase separation that has been suggested to occur in many BMGs including some Pd-rich systems.