High pressure atomic structure of Zr–Cu metallic glass via EXAFS spectroscopy and molecular dynamics simulations

ABSTRACT

In this work, we use extended X-ray absorption fine structure (EXAFS) data collected using nano-polycrystalline diamond anvil cell to study the atomic arrangement in Zr–Cu metallic glass in high pressure (HP) conditions. To reveal the microscopic details of stress accommodation mechanism, we performed molecular dynamics (MD) simulations of the HP atomic arrangement. By comparing the experimental and the calculated Zr and Cu K-edge EXAFS signal we prove the realistic character of the computer simulations. A detailed geometrical analysis of the simulated atomic configurations shows that with increasing hydrostatic pressure the local structure of Zr–Cu amorphous alloy becomes gradually dominated by Cu-centred icosahedral structural motifs involving fivefold symmetry incompatible with crystalline ordering. The variation of the short-range order is attributed to preferential straining of mechanically soft bonds between zirconium atoms.

KEYWORDS:

• Metallic glasses
• high pressure
• EXAFS
• atomic structure
• icosahedral order

Acknowledgments

We acknowledge the European Synchrotron Radiation Facility for the provision of synchrotron radiation facilities. This research was carried out with the support of the Interdisciplinary Centre for Mathematical and Computational Modelling (ICM) University of Warsaw under grant no. G75-1. PD acknowledges Dean’s grant at Faculty of Physics, Warsaw University of Technology, and JA thanks Prof. G.A. Evangelakis for inspiring discussions.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

P. Dziegielewski http://orcid.org/0000-0002-7544-3960

J. Antonowicz http://orcid.org/0000-0002-7781-7540

Additional information

Funding

This work was supported by Interdisciplinary Centre for Mathematical and Computational Modelling [Grant Number G75-1].