Cryo-Casting for Controlled Decomposition of Cu-Zr-Al Bulk Metallic Glass into Nanomaterials

Author(s)
Baran Sarac, Jeong Tae Kim, Yurii P. Ivanov, Viktor Soprunyuk, Sergey V. Ketov, Wilfried Schranz, Sung Hwan Hong, Ki Buem Kim, A. Lindsay Greer, Jürgen Eckert
Abstract

Cryo-cooled copper-mold suction casting reveals an unexpected phase separation (PS) in Cu46Zr46Al8 bulk metallic glass (BMG) by controlled atomic diffusion. The decomposed alloy cryo-cast to 193 K exhibits a remarkably lower free volume than the alloy cast to room temperature manifested by dilatometry. An unusual endotherm after the onset of relaxation registered by differential scanning calorimetry and compositional homogenization occurring on long time scales upon post-heat treatment even above the glass-transition temperature confirm the stability of the decomposed state against crystallization. As revealed by scanning transmission electron microscopy and energy-dispersive X-ray analysis, single-stage PS (cryo-cast to 193 K) results in distinct and evenly dispersed nanoscale Cu- and Zr-rich regions, whereas two-stage PS (cast to 298 K) involves further decomposition of existing Cu- and Zr-rich regions on a finer scale. Notably, PS accounts for macroscopic compressive plasticity at no expense of fracture strength. This study opens opportunities for the design optimization of homogeneously dispersed amorphous nanostructures of controllable size and composition in BMGs by single- or multistage decomposition through mold temperature control.

Organisation(s)
Physics of Functional Materials
External organisation(s)
Österreichische Akademie der Wissenschaften (ÖAW), Agency for Defense Development, University of Cambridge, Far Eastern Federal University, Sejong University, Montanuniversität Leoben, National University of Science and Technology (MISiS)
Journal
ACS Applied Nano Materials
Volume
4
Pages
7771–7780
No. of pages
10
ISSN
2574-0970
DOI
https://doi.org/10.1021/acsanm.1c01055
Publication date
07-2021
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics
Keywords
ASJC Scopus subject areas
Materials Science(all)
Portal url
https://ucris.univie.ac.at/portal/en/publications/cryocasting-for-controlled-decomposition-of-cuzral-bulk-metallic-glass-into-nanomaterials(3758fd40-e37b-4f2e-b3a6-b65a878d0030).html