Atomic structure of bulk metallic glasses and their supercooled liquid states probed by high-energy synchrotron light

作者：Georgarakis K; Yavari A R^*; Louzguine D V; Vaughan G; Botta W J

来源：Comptes Rendus Physique, 2012, 13(3): 218-226.

DOI：10.1016/j.crhy.2011.12.010

• Bulk metallic glasses
• Atomic structure
• Synchrotron light
• Supercooled liquid

Like non-metallic glasses, many bulk metallic glasses manifest a glass-transition temperature T-g during heating prior to crystallisation. While the exact nature of the atomic structure of a metallic glass depends on its thermo-mechanical history (quench-rate, plastic deformation, ... ), a unique and reproducible average atomic structure is attained if the glass transition temperature can be approached in a reversible manner. However, a metallic glass is always metastable and crystallises within a time t near or above its T-g in such a way that any reciprocal or real-space information on the fully glassy state at T >= T-g must be completed within acquisition times tau(a) << t and this condition is in general difficult to attain with conventional X-ray diffraction devices.
Here we report on experiments using high-energy, high-flux synchrotron light in the transmission for probing of the atomic structure of bulk metallic glasses. Examples are given of the determination of the isochoric glass transition T-g and the quenched-in free-volume. Finally, we report on the evolution of the atomic structure in the supercooled liquid region (T > T-g) and its role in the enhancement of glass formability.

• 出版日期2012-4