Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 38: Liquid and Amorphous Metals
MM 38.8: Vortrag
Mittwoch, 28. März 2012, 16:45–17:00, H 1029
Ultrafast Heating of Metallic Glasses using a Multistep Rapid Capacitor Discharge — •Stefan Küchemann1, Jonas Rübsam1, Carsten Mahn1, Marios D. Demetriou2, William L. Johnson2, and Konrad Samwer1 — 11. Physikalisches Institut, Universität Göttingen, 37077 Göttingen, Germany — 2Keck Engineering Laboratories, California Institute of Technology, Pasadena, California 91125, USA
Generally the study of the specific heat of metallic glasses is limited to temperatures below and close to TG. The incipient crystallization process above the glass transition temperature prohibits the study of this quantity in the supercooled liquid region.
In this contribution specific heat measurements using a novel Multistep Rapid Capacitor Discharge (MRCD) technique are presented. With MRCD melt-spun Pd-, Ni- and Fe-based samples were heated up homogeneously with typical heating rates in the order of 106 K/s. The very high heating rates raise the stability of the undercooled melt and thus enlarge the temperature difference Δ T=TX−TG up to 400 K or even suppress crystallization completely.
After a first capacitor discharge the sample reaches the supercooled liquid region while under nearly adiabatic conditions additional discharges allow specific heat measurements in the undercooled liquid.
Financial support by DFG is gratefully acknowledged.