TY  - JOUR
AU  - Neuber, Nico
AU  - Gross, Oliver
AU  - Frey, Maximilian
AU  - Bochtler, Benedikt
AU  - Kuball, Alexander
AU  - Hechler, Simon
AU  - Gallino, Isabella
AU  - Busch, Ralf
TI  - On the thermodynamics and its connection to structure in the Pt-Pd-Cu-Ni-P bulk metallic glass forming system
JO  - Acta materialia
VL  - 220
SN  - 1359-6454
CY  - Amsterdam [u.a.]
PB  - Elsevier Science
M1  - PUBDB-2021-04560
SP  - 117300
PY  - 2021
AB  - 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)<sub>42.5</sub>Cu<sub>27</sub>Ni<sub>9.5</sub>P<sub>21</sub>. 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 structurally influencing thermal properties such as enthalpy and heat capacity.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000705535300008
DO  - DOI:10.1016/j.actamat.2021.117300
UR  - https://bib-pubdb1.desy.de/record/471712
ER  -