Please use this identifier to cite or link to this item: doi:10.22028/D291-39392
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Title: On the thermodynamics and its connection to structure in the Pt-Pd-Cu-Ni-P bulk metallic glass forming system
Author(s): Neuber, Nico
Gross, Oliver
Frey, Maximiliam
Bochtler, Benedikt
Kuball, Alexander
Hechler, Simon
Gallino, Isabella
Busch, Ralf
Language: English
Title: Acta Materialia
Volume: 220
Publisher/Platform: Elsevier
Year of Publication: 2021
Free key words: Thermodynamics
Bulk metallic glass
Noble metal
Synchrotron X-ray diffraction
structural analysis
DDC notations: 500 Science
Publikation type: Journal Article
Abstract: Contrary to basic hard sphere structure models, recent studies revealed, significant structural differences between Pt-Cu-Ni-P and Pd-Cu-Ni-P metallic glass-forming liquids with the same stoichiometry. To cover the compositional space between both systems, platinum is subsequently replaced by palladium in the composition (Pt/Pd)42.5Cu27Ni9.5P21. For this systematic set of alloys, the thermodynamic properties, such as isobaric heat capacity, enthalpy and Gibbs free energy are assessed. A systematic drop of the Gibbs free energy difference between crystal and liquid, providing a lower estimate of the driving force for crystallization was observed, underlining the high glass-forming ability of the Pd-rich systems. Contrary to kinetic fragility data, a change of the thermodynamic fragility can be observed, drawing the picture of an increasing thermodynamically strong behavior with rising Pd-content. Further, the temperature induced changes of the total structure factors S(Q) were monitored using high-energy synchrotron X-ray diffraction. Focus was laid on the changes on the medium-range length scale, by analyzing changes of the first sharp diffraction peak. Here a good correlation of the changes in peak-width and the thermodynamic fragility was found. From the determination of the excess enthalpy, large amounts of residual enthalpy in the glassy state were observed for the Pt-rich alloys, supporting the increased ductility of these alloys. The current findings further carve out the different roles of the topologically similar Pt and Pd in the Pt/Pd-Cu-Ni-P alloy system and how the change of the structural motifs on the medium range order is influencing thermal properties such as enthalpy and heat capacity.
DOI of the first publication: 10.1016/j.actamat.2021.117300
URL of the first publication:
Link to this record: urn:nbn:de:bsz:291--ds-393929
ISSN: 1359-6454
Date of registration: 28-Mar-2023
Faculty: NT - Naturwissenschaftlich- Technische Fakultät
Department: NT - Materialwissenschaft und Werkstofftechnik
Professorship: NT - Prof. Dr. Ralf Busch
Collections:SciDok - Der Wissenschaftsserver der Universität des Saarlandes

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