Monotropic polymorphism in a glass-forming metallic alloy

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Authors

  • D. Leutenegger
  • J. E.K. Schawe
  • P. Maris
  • R. Schäublin
  • Jörg F. Löffler

External Organisational units

  • Eidgenössische Technische Hochschule Zürich
  • Analytical

Abstract

This study investigates the crystallization and phase transition behavior of the amorphous metallic alloy Au70Cu5.5Ag7.5Si17. This alloy has been recently shown to exhibit a transition of a metastable to a more stable crystalline state, occurring via metastable melting under strong non-equilibrium conditions. Such behavior had so far not been observed in other metallic alloys. In this investigation fast differential scanning calorimetry (FDSC) is used to explore crystallization and the solid-liquid-solid transition upon linear heating and during isothermal annealing, as a function of the conditions under which the metastable phase is formed. It is shown that the occurrence of the solid-liquid-solid transformation in FDSC depends on the initial conditions; this is explained by a history-dependent nucleation of the stable crystalline phase. The microstructure was investigated by scanning and transmission electron microscopy and x-ray diffraction. Chemical mapping was performed by energy dispersive x-ray spectrometry. The relationship between the microstructure and the phase transitions observed in FSDC is discussed with respect to the possible kinetic paths of the solid-liquid-solid transition, which is a typical phenomenon in monotropic polymorphism.

Details

Original languageEnglish
Article number234002
Number of pages10
JournalJournal of Physics Condensed Matter
Volume30.2018
Issue number23
DOIs
Publication statusPublished - 18 May 2018