Monotropic polymorphism in a glass-forming metallic alloy
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in: Journal of Physics Condensed Matter, Jahrgang 30.2018, Nr. 23, 234002, 18.05.2018.
Publikationen: Beitrag in Fachzeitschrift › Artikel › Forschung › (peer-reviewed)
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TY - JOUR
T1 - Monotropic polymorphism in a glass-forming metallic alloy
AU - Pogatscher, Stefan
AU - Leutenegger, D.
AU - Schawe, J. E.K.
AU - Maris, P.
AU - Schäublin, R.
AU - Uggowitzer, Peter J.
AU - Löffler, Jörg F.
PY - 2018/5/18
Y1 - 2018/5/18
N2 - 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.
AB - 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.
KW - amorphous
KW - metals
KW - phase transformation
KW - polymorphism
UR - http://www.scopus.com/inward/record.url?scp=85047966329&partnerID=8YFLogxK
U2 - 10.1088/1361-648X/aac054
DO - 10.1088/1361-648X/aac054
M3 - Article
AN - SCOPUS:85047966329
VL - 30.2018
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
SN - 0953-8984
IS - 23
M1 - 234002
ER -