Structural characterisation of Cu-Zr thin film combinatorial libraries with synchrotron radiation at the limit of crystallinity

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Authors

  • O. Milkovič
  • G. Mohanty
  • R. Ipach
  • L. Pethö
  • J. Milkovičová
  • X. Maeder
  • T. E.J. Edwards
  • P. Schweizer
  • M. Coduri
  • K. Saksl
  • J. Michler

External Organisational units

  • Eidgenössische Materialprüfanstalt, EMPA
  • Institute of Inorganic Chemistry
  • Faculty of Engineering and Natural Science
  • Technical University of Košice
  • University of Pavia
  • P.J. Šafárik University

Abstract

We report for the first-time combinatorial synthesis of thin film metallic glass libraries via magnetron co-sputtering at the limit of crystallinity. Special care was taken to prepare extremely pure CuZr films (1–2 µm thickness) with large compositional gradients (Cu18.2Zr81.8 to Cu74.8Zr25.2) on X-ray transparent polymer substrates in high-vacuum conditions. Combined mapping of atomic structure (synchrotron radiation) and chemical composition (X-ray fluorescence spectroscopy) revealed that over the entire composition range, covering multiple renowned glass formers, two phases are present in the film. Our high-resolution Synchrotron approach identified the two phases as: untextured amorphous Cu51Zr14 (cluster size 1.3 nm) and textured, nanocrystalline α-Zr (grain size 1–5 nm). Real space HR-STEM analyses of a representative composition substantiate our XRD results. Determined cluster and grain sizes are below the resolution limit of conventional laboratory-scale X-ray diffractometers. The presented phase mixture is not permitted in the Cu-Zr phase diagram and contrary to existing literature. The phase ratio follows a linear trend with amorphous films on the Cu-rich side and increasing amounts of α-Zr with increasing Zr content. While cluster size and composition of the amorphous phase remain constant thorough the compositional gradient, crystallite size and texture of the nanocrystalline α-Zr change as a function of Zr content.

Details

Original languageEnglish
Article number110675
Number of pages12
JournalMaterials and Design
Volume218.2022
Issue numberJune
DOIs
Publication statusPublished - Jun 2022