Berlin 2018 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 46: Liquid and Amorphous Metals

MM 46.3: Vortrag

Mittwoch, 14. März 2018, 17:30–17:45, TC 010

Elastostatic Reversibility: Structural Changes in Thermoplastically Formed Metallic Glass — •Baran Sarac¹, Christoph Gammer¹, Liang Deng², Eunmi Park², Yoshihiko Yokoyama³, Mihai Stoica⁴, and Jürgen Eckert¹ — ¹Erich Schmid Institute, Leoben, Austria — ²IFW Dresden, Dresden, Germany — ³Tohoku University, Sendai, Japan — ⁴ETH Zurich, Zürich, Switzerland

Albeit high processing capabilities of BMGs, thermoplastic forming (TPF) can severely degrade their mechanical and physical properties. Present work places an importance on elastostatic loading (ESL) which not only fully recovers the lowered room temperature plasticity originated from TPF or post-cryostatic conditions, but also activates a rejuvenation mechanism by yielding an extended resistance against strain softening. The drop in the supercooled liquid region and crystallization enthalpy measured by differential scanning calorimeter are found to be temporary, and can be reversed to its initial condition. Individual nanobeam diffraction patterns taken by the fluctuation electron microscopy are acquired with a probe size of 1.2 nm. Normalized variance of a series of nanodiffraction patterns of the post-ESL sample reveals height decrease in the first broad peak of normalized intensity variance, suggesting the modifications in the medium-range order which in turn dramatically restores mechanical and thermal properties. The combination of TPF and post-ESL treatment in BMGs can open a new avenue for ultra-high mechanical and thermal performance micro- and nanomechanical devices for biosensors, MOSFETs, and robotics.