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doi:10.22028/D291-39392
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 Fragility 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: | https://www.sciencedirect.com/science/article/abs/pii/S1359645421006807 |
Link to this record: | urn:nbn:de:bsz:291--ds-393929 hdl:20.500.11880/35517 http://dx.doi.org/10.22028/D291-39392 |
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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