Regensburg 2019 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 36: Liquid and Amorphous Metals

MM 36.3: Talk

Thursday, April 4, 2019, 10:45–11:00, H46

Crystallization behavior of a bulk metallic glass-former — •Mark Stringe, Joachim Bokeloh, Harald Rösner, and Gerhard Wilde — Institute of Materials Physics, University of Münster, D-48149 Münster

Crystallization plays a crucial role not only regarding the production of metallic glasses, but also concerning the stability of these systems. This stability is linked to the corresponding ability of atoms to rearrange. The movement of atoms is also affecting the glass forming ability and thus the crystallization of the undercooled liquid.

With a variation of scanning rates of calorimetric measurements it is possible to analyze crystallization kinetics. The measurements are performed with conventional differential scanning calorimetry (DSC). Higher scanning rates are realized using a custom-built fast DSC according to the concept of C. Schick et al. [1]. With this fast scanning calorimetry (FSC) samples with a mass of the order of micrograms are measured with scanning rates up to 10.000 K/s.

An AuCuSiAg bulk metallic glass with low melting point is analyzed. In FSC it is possible to reach cooling rates to quench a glass in-situ. Thus the critical cooling rate can be determined directly and activation energies for crystallization of the supercooled liquid are obtained from Kissinger analyses.

Depending on the degree of undercooling, the system shows a change in the crystallization behavior of the undercooled liquid suggesting a change in kinetics.

[1] Zhuravlev E, Schick C, Thermochimica Acta 505 (2010) 1-13